Supercharging (this time, it's real)

[Guest MauiWowee]

[/image]

[Guest F14CRAZY]

"The only racing that ever mattered, is on the streets"

-F14

[2seater]

I agree with Ryan 100% that you shouldn't use the LN3 MAF sensor, the construction is completely different, as can be seen, although my testing indicates the calibration is essentially identical to the LN3. The location of the O-ring being different will cause a vacuum leak as well as the sensor wires not being inside a symetrical opening. What are the two rows of numbers on the L67 MAF sensor? I don't suspect the MAF at this time, it appears to be the correct type, unless it is bad. I think you are working with a 1990 engine and ECM and this one will go into closed loop operation at 130* F, observed many times. Your fuel pressure reading still seems funky? Unless that regulator is damped somehow, the pressure should snap up and down when you blip the throttle. It will slowly change with a slow change in throttle, but I would think the pressure should actually do down at a constant engine speed of say 2000 rpm vs idle, since the engine vacuum at essentially no load should be higher. The only caveat is the s/c itself and the comment that it picks up the vacuum signal from below the blower. I think I remember you said the boost bypass is blocked in the closed position. Maybe there is a slight boost pressure, or a reduction in vacuum from the blower spinning? Tee a vacuum gauge into that line to see what it is seeing? Actually, just disconnect the vacuum from the regulator and plug the line. The fuel pressure should now be at a fixed value of around 3 bar, 43.5 psi, if the regulator is calibrated the same as the LN3, and it should not vary with engine rpm or whatever you do with the throttle. If it changes, something odd is going on. If it drops when you mash the throttle, fuel delivery is inadequate, for whatever reason. The higher fuel pressure should gradually move the BLM lower since the pressure and fuel delivery will be higher than normal. The O2 must be connected and up to temperature for this adjustment process to work and it will take a little while.

The TV (throttle valve) cable controls the shift point on these transaxles. The modulator controls line pressure and shift firmness. They are apparently a little different than most mechanical transmissions in that the two functions are pretty much divorced from each other. On most systems the two items interact more with each other. With the cable disconnected I would expect the trans. to upshift earlier than normal. In theory it shouldn't do any harm, at least short term, but the s/c engine produces a lot more torque and early shift points will tend to place more strain on the system, and load the engine more than normal. Best bet would be to get it connected and adjusted properly. For your testing in park/neutral, it won't matter.

For the record, I run Autolite 103 plugs gapped @ .048" with the stock Magnavox ignition. This is a cold plug, two ranges below stock. A 104 would be better choice, one range colder than stock as a good starting point. Just my opinion, but platinum plugs don't perform well in a boosted engine, especially Bosch, but there are a lot of different opinions on this.

[Guest F14CRAZY]

I swore that someone suggested swapping the MAFs. But at any rate, I'll get the part number later and switch back.

As I said, the pressure does briefly blip up when I blip the throttle, but drops down almost immiditely (spelling?) for the engine bogs out.

I'll get a pressure reading with the regulator vacuum disconnected.

I do have platnium plugs. Should I swap them out?

[OldsTrofeo]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I got a reply from Ryan...

<span style="font-weight: bold">Philip, if your fuel pressure is dropping off with higher RPM's or more boost present, the fuel system is not adequate for the job. Can I assume you are using the stock L67 fuel rail and pressure regulator along with the injectors?</span></div></div>

He programmed your chip without knowing what injectors you're using? That could be a problem!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"><span style="font-weight: bold">

Don't set the plug gap at 0.025". That is far too small. A plug gap setting of 0.050" is what I would use.</span></div></div>

I hear this *all* the time! It's amazing what people assume without testing. If you're getting a misfire, this will often clear it up on a DIS system. I never set supercharged engines larger than .045", usually .025-.035".

[Guest F14CRAZY]

He knew of the injectors I was going to use. I said so in the form I filled out for the memcal program. He's just checking to be sure I'm still using them and didn't go ahead and use the LN3 injectors.

I am using a Delco coil pack

[gmtuners.com]

If it is ok with Philip, I think too it would be a good idea to continue the discussion here so the bulk of the Reatta community can use it as a reference...

Yes, I knew what injectors philip was using when I did the chip but the reason why I asked again was because he was talking about swapping parts back on from the LN3. I just wanted to make sure.

I would like to take a moment and explain what I have done with Philip's programming. I have tried a unique idea in which I have attempted to marry as much of the L67 programming as I could with the LN3 computer system. I am confident we can get the LN3 computer to work with the supercharger, although I am sure it is going to take some trail and error until we get it working right. For this application, I suggest that Philip use the L67 throttle body and MAF sensor since that is what the chip I did for him is programmed for.

As far as INT (Integrator) and BLM (Block Learn) counts are concerned, here is how that factors into the fuel equation...

Integrator is short term fuel trim. The median value is 128. The computer will adjust this value rapidly in order to satisfy stoich fuel ratio (14.7:1). Any number higher than 128 tells us that the computer is having to add fuel to the base fuel map in the programming in order to get the A/F ratio rich enough to meet the 14.7:1 stoich value. Any number lower than 128 tells us the computer is having to remove fuel from the base fuel map in order to lean out the A/F ratio to meet the 14.7:1 stoich value. These same numbers apply to the BLM counts.

The BLM is long-term or stored fuel trim. Most GM cars have a 16 BLM cells, or memory points where the learned fuel trims can be stored. The cells are divided up by RPM and LV8 (load). BLM learning is not always enabled. Even if the system is in Closed Loop, there are still additional parameters/requirements that must be met in order for BLM cell learning to take place. These parameters are different from vehicle to vehicle.

In any case, if your INT counts are hovering around say the 160's, you should notice the BLM counts slowly moving towards that level. As they do, the INT's should come back down. Once the INT comes back down to 128, the BLM's will stablize and the ECM may decide to store that new BLM value to the approprite memory cell for future use (lookup).

Also in these computers there is a function known as PE (power enrichment). On stock LN3 programming, the ECM is instructed to enter "PE mode" around 50-60% throttle, depending on the RPM level. On stock L67 programming, PE mode is entered at about 40-50% since boost can build on these engines with relatively low throttle openings. Nevertheless, when PE mode is active, the INT and BLM counts will freeze, no BLM cell learning will be enabled, and the O2 sensor signal will be ignored (the computer will not attempt to make any adjustments to the fuel trims during PE). That is why we need to know what the O2 voltage or exhaust A/F ratio is doing when in PE mode. A wide-band O2 sensor is far more accurate in this area, but the factory narrow-band O2 sensor does give us a ballpark idea of what the fuel mixture is. However, if misfires are occuring, this will allow raw oxygen to enter the exhaust system which will throw O2 sensor readings off.

There are a couple of things Philip and I need to figure out with his car. We have already determined the fuel pressure isn't rising to spec of the L67 engine. Once he gets the fuel pump replaced (I would advise changing the fuel filter at the same time if it hasn't recently been done), we can proceed with further diagnosis. There is nothing more difficult than trying to "tune-around" a mechanical or electrical issue that exists; especially on a project like this.

-ryan

[Guest F14CRAZY]

Thank you Ryan.

I just came in for dinner, but I'm working on the fuel pump right now. I've got the tank down and harness disconnected. The tank straps and fuel lines look to be in good condition.

The tank was over half full, so I connected a longer hose under the hood where the fuel lines connect to the rail and applied power to the oh-so-mysterious green connector under the hood by Teves. I pumped the tank dry (pump wont be used again anyway). A lot easier this way than having to work with a heavy, dangerous tank.

When I get it running pretty darn close to decent, I could probably take a day and come down and see you, Ryan, so you can do the finer tuning.

[Guest F14CRAZY]

Hey, I got the new fuel pump put in! Took a few hours but wasn't that bad. As Ryan suggested, I used one prescribed for an '89 Turbo 3.8L Firebird.

I did some fuel rail testing. At warm idle, I'm reading 38 PSI. I disconnected the vacuum line for the fuel pressure regulator, and the pressure stayed the same. When the throttle is blipped from idle (and it bogs) I very briefly read about 50 psi. I recorded the same thing happening, both with the vacuum line connected and disconnected. At WOT, I read 42 PSI. At this point, I can slowly get up to 4600+ rpm, just have to get there slowly.

New warm idle ECM readings today with the new pump...

ED01, TPS: .48

coolant temp: about 180 F

ED06, injector pulse width: 4.4-4.6

ED07, osygen sensor voltage: 0.10-0.73 (quickly, randomly changing)

ED08, spark advance: 18 degrees

ED16, ESC knock retard: 0 degrees

ED17, OLDPA3 knock sensor activity: 109

ED18, oxygen sensor cross counts: 2-12

ED19, fuel integrator: 121-127

ED20, BLM: 123-124

ED21, air flow: 6.7-6.9

ED23, MAT: 16 degrees C

ED98, ignition cycle counter: 0

From what I know and the looks of it, the integrator and BLM are about normal, right? In a few minutes I'll have the ECm readings when bogging out

[Guest F14CRAZY]

I got these readings, with the motor bogging out, by generously stepping on the throttle (maybe halfway?) quickly and recording the readings. I did it once for every sensor reading. I'd let the throttle get up to about 1500 rpm with it bogging (it very slowly comes up, but still runs bad).

ED07, oxygen sensor: still all over the place

ED17, OLDPA3 knock sensor activity: 186

ED18, oxygen sensor cross counts: 3-6

ED19, fuel integrator: 121-127

ED20, BLM: 130-133

You guys want any different readings?

[Guest F14CRAZY]

I haven't driven the car yet. In fact, the rear wheels are still off (had to kinda remove the sway bar to get the tank in/out). I still have to work on that tranny cable before taking it for a spin.

Ryan: at this point, do you suppose at this point I could make a day trip with the car to you so you can really see what's going on and tune it? Are you more or less readily available? It's running good enough to drive at the speed limit and from the ECM data, isn't running acutely bad. The internet is cool, but as you know and we know, it's hard to tune a car a few hundred miles away.

[Guest maybe2fast]

so the new fuel pump didn't help?

[Guest F14CRAZY]

It did not help. It doesn't run any better.

However, do note, that fuel pressure is now right where it should be. It's 38 PSI at idle, which Ryan said it ideal. I used to be around 30.

Is the fuel regulator faulty?

[sahein]

It is time to check the basics again.

[padgett]

17 degrees advance sounds quite low but may be remapped for premium fuel (mine runs about 23 degrees at idle and hits 40 degrees on a blip, I would expect you to see at least 35 degrees advance by 2000 rpm with light load since no boost is involved.

You do not seem to be getting knock retard (OLDPA3 often increments on startup but should not be changing at idle).

Again, if you rub your finger inside the tailpipe, does is come away black ?

Remote possibility: clogged catalytic converter, will act like a potato in the exhaust pipe. Might try a brief run-up with the headpipe disconnected since you have it in the air and see if it still bogs.

Just for S&G if you still have your original PROM, might try that. Without load in the garage you should not get into any boost anyway and would be a good test.

[Guest F14CRAZY]

I have a '90 Lesabre memcal which runs a Reatta LN3 perfectly fine, so I'll try that.

The less knock retard the better, right?

No abnormal amount of carbon/blackness in the tailpipe

The cat was replaced last year. But would a clogged cat still let the motor run at steady high RPMs or WOT fine?

Should the fuel pressure go up with RPM? Ryan said that 38 PSI should be idle, and then rise about 1 PSI for about every pound of boost. At WOT, I'm still reading about 40. Could the regulator be bad?

Could the MAF be bad? The one I'm using is not known to be good, though the yard said the motor ran fine in the Bonneville it came out of 33 days before I bought it

[gmtuners.com]

First of all, Philip can no longer run a stock Reatta or any other stock LN3 mem-cal (chip) in his car because he is using the larger L67 injectors. If he tries using a LN3 chip, he will flood out his engine.

It sounds like your fuel pressure readings have improved with the new pump, however, I am troubled by the fact the fuel pressure isn't changing when you unplug the fuel pressure regulator. With the engine running at idle, with the vacuum line plugged in, your fuel pressure should be 35-38psi; as you indicated you had. However, that pressure should have jumped to approx 42-45psi when you unplugged the regulator. Was there vacuum present at this vacuum line at idle? If not, there must be a vacuum leak somewhere. As far as fuel pressure under boost is concerned, again; I don't have specific specs but I am pretty sure it should be above 50psi at about 10psi of boost.

Philip, you INT and BLM counts look MUCH BETTER than they were. However, since the bogging problem hasn't changed whatsoever (even though the INT and BLM counts have improved) tells me we MIGHT be dealing with a mechanical issue here. Checking for a clogged catalytic converter is a VERY GOOD idea as well. As the guy said earlier, unbolt your exhaust system from the manifold and see if the bog still exists. But I am not ready to rule out a computer tuning issue just yet. The O2's shouldn't move around under "WOT" but since you are getting a bog, or misfire, this is probably the cause of the irratic readings.

As far as bringing the car to me, that shouldn't be a problem. Contact me via email and we will discuss time and date.

-ryan

[Guest F14CRAZY]

There for sure was vacuum when I unplugged the regulator. I felt and heard it. I'll check around for leaks again, but I can say that there's at least something there.

I'll get an oxygen sensor reading at WOT.

I bought plugs and wires which I'm going to do for good luck. I'll recheck the TPS. I bought the AC Delco equivelent of the 104s that 2seater mentioned.

[Guest maybe2fast]

I wonder since you are using the LN3 heads and with the rear exhaust manifold issue the motor is choking on its own exhaust?...

[padgett]

Without a load the peak fuel flow and LN3 exhaust pipes are not going to make a difference. What I hear is that the engine bogs just on free revving.

Really wonder if there is an advance curve issue.

[Guest F14CRAZY]

Today I picked up some new LN3 plug wires and AC Delco R42LTS plugs, the equivelent of the Autolite 104s (Advance didn't have enough).

I pulled my current Autolites out, and I don't know how, but I they were gapped at 0.060 up to 0.065, pretty far off from the 0.048 that 2seater suggests and that I used.

Got them in and fired it up. No noticible change. Blast, I thought I was on to something. I did recheck that the plug wires were connected right.

At operating temperature I ran it up to WOT and held it for a few seconds to get the oxygen sensor reading (it's around 0.67). Not sure what RPMs were but it was above 4k rpm. I got out to check the engine (returned to idle) and found that the exhaust headers were glowing brightly . I shut the system down. I don't think that's a very good thing.

Where to now?

[Guest F14CRAZY]

Is that a sign of a clogged cat? Haven't got to trying it with it disconnected yet

[Guest maybe2fast]

I think with the SCer the exhaust manifold restriction is backing up the exhaust with the added cat restriction even with an operational cat it is still a restriction. I think it is a restricted exhaust.

1) LN3 rear exhaust manifold restriction

2) cat+LN3 rear exhaust manifold restriction

at least cut the cat off

[Guest EDBS0]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> the exhaust headers were glowing brightly </div></div>

Photos please!!!

Would that be a sign of greatly retarded timing?

[padgett]

"the exhaust headers were glowing brightly" - usually means waaay lean though suppose a really retarded spark could result in fulel burning in the exhause pipe. What does the inside of the tail pipe look like - whill be almost white if way lean, grey if normal and black if too rich.

[Guest F14CRAZY]

The tail pipe looks to be normal. I get some carbon when I run a finger inside, of course, but not an abnormal amount. I guess it's something that Ryan needs to analyze at the car.

Sorry I didn't have my camera with me, but they were bright red hot. I don't freak out at things, but if I did I would have.

[Guest F14CRAZY]

The hot exhaust headers seem to only come up when the engine is operated at or near WOT. I have idled it for long periods and held speed at 1500 rpm for a few minutes at a time before, and never saw them to be glowing hot or look abnormal.

I'm thinking that the restricted exhaust/cat may be the answer. I'll let you guys know soon. We've got some family from the Philippines over for a while, so things might be a little slow at times

[89REATTAJIM]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You two make a beautiful couple, Philip!!

Guess I'll have to tell my girls to keep looking for a son for me!

You'll be a hard act to follow, of course!!

I told the girls - Requirement #1 - he must like Reatta convertibles, (his own, not mine!!)

The rest is up to their own taste. But, I'll still have some input!

Based upon thier respective choices, there may a special "wedding gift" involved! </div></div>

F14, You may want to reconsider this offer. May not hurt to have a spare Reatta and/or parts available. Seriously, looks like you have a slight setback, but between yourself & all the help you're getting, I'm sure you will be on the road soon. Good Luck.

[Guest maybe2fast]

this makes alot of sense seeing he can baby it up to speed but can't step on it.

[2seater]

The injector pulse width seems very high for idle? Granted the fueling numbers look much better, but the fuel pressure change, or lack of it, when disconnecting the vacuum is definitely not right. Did you leave the vacuum line disconnected (plugged) and try the "rev test"? The pressure should not change, or change very little as the demand changes. The glowing manifolds are either retarded timing or dead lean, as suggested by others. The timing seems a bit low for idle, that is more like the timing for full load and boost, but it isn't retarded enough to account for the glowing pipes. If the O2 locked around .67 that's awfully lean for a high load, but I don't think your are loading the engine much unless it is in gear? Is it possible that the fuel rail is plugged or something? If the pump is new, and the filter clean, the pressure appears to be acting oddly. The pressure tap is right on the lower part of the regulator, right? If that is the case the fuel would have to pressurize the entire rail first and if the pressure remains constant with the vacuum disconnected, idle and revved, the rail "should" be flowing okay. I know you said you had the lines backwards once and reversed them. Is it possible they are connected backwards? The return line should be connected to the regulator. The rail pressure is regulated on the outlet end, not the inlet. Please disconnect both lines and place them in a small container to catch the fluid and momentarily make the pump run. Be careful of sparks and the force of the fuel flow. The pressure line must be connected to the non-regulator end of the rail. Ryan knows plenty when it comes to the tuning of the chip and it shouldn't be far enough off to cause these problems, and even though other problems may exist, like a massive vacuum leak, or plugged exhaust, it still sounds like a fuel delivery problem. The big bog sounds just like mine when the filter plugged. Do you have a vacuum gauge? A plugged exhaust will show up as a gradual decline in the vacuum reading at a steady elevated rpm, like below where the bog occurs.

[Guest F14CRAZY]

I had vacuum to the regulator connect when doing the rev test...I will try it again tomorrow with is disconnected.

True, engines in neutral really have no load on them (ie: being on the freeway with cruise control on, and then dropping it in neutral).

I suppose the fuel rail could be plugged, but when I removed the injectors on it to install new seals, residual gas in it flowed out freely. Possible, but very very unlikely.

I'm holed up the night. I wish I could go out and check, but I don't remember where the pressure test fitting is in relation to the regulator on the rail.

I know for sure, that I have the pressurized line from the pump connected to the fuel rail so that the pressure test fitting is closest to the pressurized gas...the fitting is between the injectors and the positive pressure line.

No vacuum leaks. I did mention what sounds like an awful leak at startup, but it goes away pretty soon after starting up.

I'll recheck the lines tomorrow morning. I'm sure going to feel like a dumbazz if they're connected wrong

So tomorrow...before I go to school I'll check the lines, cuz I can report back on the board during class. I have a half day tomorrow, so work can commence. I'll try the lines first. If it's not the lines, I'll go for diconnecting the cat (I don't have a vacuum gauge).

"Lean" means that there's too much gas and it's going out of the engine unburned, right?

When I changed out my pump yesterday I attached a hose to the positive pressure line under the hood (disconnected from fuel rail) and applied 12v to the green terminal and pumped it into my cans . So, at least I'm certain of which line is the positive pressure one from the return line.

Thanks guys. The continuing saga...

[Guest MauiWowee]

Post deleted by MauiWowee

[jonlabree]

May I sugest the you try the old injectors as you seem to be

putting out the fire when you punch it. You need to lean it out.

[Guest F14CRAZY]

I had my truck parked outside this morning, so I didn't get to pass through the barn, and thus, I forgot to check the hoses on my fuel rail! But as I said, I have a half day, so I'll be able to check and let you guys know later this morning.

I will be not-pleased if I find I disconnected them wrong

[Guest F14CRAZY]

Checked my fuel lines...yes, they're the way they should be. Regulator end is connected to the return line.

I'll get to disconnecting the cat today

[Guest F14CRAZY]

Oooops. Sorry to Ryan and anyone thats read, but it is NOT the cat. I did more revving when I got it out of the garage and it isn't performing any better. Don't know what happened earlier...with the cat disconnected, I started it up, idled for a few seconds, and gave a few steps on the gas and it was fine.

False alarm. Our run-bad condition is not because of a clogged cat

[jonlabree]

If you headers are red hot, you are burning gas outside of the cylinders,

which means you are flooding out the engine when you punch it. You need to

find away to cut back on the fuel supply.

[gmtuners.com]

Philip: about this glowing exhaust issue... Is this the first time this has occurred? If so, something has changed since you swapped out plugs and wires (assuming that is the last thing you changed). Doublecheck your firing order.

I have only experienced glowing manifolds a couple of times over the years and the cause was incorrect ignition and/or cam timing or incorrect firing order (ign wire hookup). I haven't personally experienced a lean condition causing this to happen, at least not at very light loads. Furthermore, if the O2 voltage is still moving around and is not stuck rich or lean, than the ECM isn't having trouble adjusting the A/F ratio so I doubt that is the issue...assuming the O2 sensor is not sending a false signal to the ECM or being mislead by a misfire condition.

Again, I would try unhooking the cat just to see if there is any change with the bogging. As far as the stock LN3 exhaust manifolds being a restriction; the very first L67 swap I did a 1992 L67 was used which had a very poorly cut hole in the rear exhaust manifold for the exhaust dump (outlet to the cat). After discovering this poorly designed restriction, I promptly ported it out and performance increased. However, previous to that, no misfires or bogs were occuring because of it's presence. Therefore I am not inclined to believe this is causing the problem.

Philip, I'd advise you not try running the stock LN3 injectors (which flow 19 lb/hr) with the chip I have done for the SC because the L67 programming is set up for 29 lb injectors. However, you can try running the LN3 injectors if you reinstall a stock LN3 chip; although I strongly suggest you DO NOT attempt any boost operation. The LN3 programming will not give the now-supercharged engine enough fuel and will give it too much timing under boost which can result in serious damage.

[gmtuners.com]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Haha! I got the cat sawzall-ed off and she revs up fine! We're calling about having a new cat installed </div></div>

Outstanding. Check with Jegs or Summit as you can get hi-flow cats for about $50 or so.

[Guest F14CRAZY]

This is not the first time I've seen glowing pipes. I did see it more than once, and was always after running near full throttle. I thought I posted it somewhere, but I checked and I didn't.

At first, after disconnecting the cat, I was convinced that it was the problem. But after a minute or so at idle, it got back to bogging again. I must have got a bit too excited there and wasn't paying attention.

One asked if the fuel pressure would shoot up when revved with the vacuum for the rail fuel removed...it behaves the same, whether connected or not.

I don't know what to try next. I'll re-recheck the ignition wires I guess.