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Today I bought my own fuel pressure gauge and a new Bosch oxygen sensor. Now, I can get my own readings whenever I please.

During the 1st two seconds with key on, engine off, I read 40 psi. Then, it drops to 38. Within 5 minutes, it drops to 30 psi.

Is this normal, or a sign of an injector stuck open? I'm still going to get a new pump (Ryan suggests one for a '89 Turbo Trans Am) and mess with that, but wanted to give you these readings and let you guys know that I have my own gauge and can check it whenever you think it should be.

After installing the new oxygen sensor, should I go ahead and start the car and report back new ECM readings? Thank you guys so much for all the help and advice on this project. A big, complex, expensive puzzle. And sometimes, you need to make your own peices. Or make some pieces fit. But we'll figure it out smile.gif

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I think (Padgett can speak for himself of course) he means if the fuel pressure is too low, the ECM must compensate by increasing the injector pulse width to get the mixture where it should be. The adjustments show up in the long term fuel trim, or BLM. The injector is designed to flow a certain amount of fuel at a specific pressure. If the pressure is low, the injector will flow less than expected. The injector cannot adjust itself, it is either open or closed, controlled by the ECM. The ECM simply holds the injector open longer to get more fuel, but there are limits as to the amount it can compensate. Two things work against you at higher rpm, the fuel demand increases and the time to get the fuel into the engine decreases (two complete revolutions). At 5000 rpm there is only 20% of the time available to get the fuel into the engine as at 1000 rpm, plus there will generally be a greater demand, especially if accelerating, where the fuel mix will need to be richer than for cruise. Even if it can be made to run at low speed, the demand caused by accelerating will probably outpace the delivery capability. In short form, it appears you O2 sensor is working pretty much normally, your cross counts were decent, but if lack of fuel is the real cause, the O2 sensor can't do anything about it. The cross counts will slow down or possibly stop since it cannot get the engine to cycle rich and lean as it should. The money will be better spent buying a diagnostic tool like the fuel pressure gauge.

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The drop in fuel pressure seems a bit rapid. It will decrease over time, part of the reason for the two second pump run with the key on, it will not hold indefinitely. It is possible there may be a small leak in an injector or possibly the regulator is allowing the pressure to drop, for the same reason. It could be these items need to be cleaned? Injectors rarely fail, and if they do it will probably just not open. Professional cleaning can be done for a reasonable fee, but you can try this for almost no money: get a good carb cleaner, Berryman is cheap and works very well (a lot of others are junk IMHO). Remove the injectors, cycle them open and closed by applying 12 volts and ground to the connection and spray the carb cleaner backwards through the injector. This is messy and you need to protect yourself from the spray. You might make an adapter of some sort to sort of seal the spray tube to the end of the injector. Do not hold the injector open for long or it will get hot. You only need hold it open for a few seconds to get a couple of squirts through it. This is crude but it will help if there are deposits holding it open. Actually you can flow through it in both directions when open but there are different types of injectors and it may now want to flow backwards too easily. You can do the same for the fuel pressure regulator, just apply some vacuum to the nipple to open the regulator fuel passage and spray carb cleaner into the inlet and outlet for the fuel. I do not know what the base fuel pressure should be for that particular engine. Back around the time of our cars, the most common pressure was generally around 3 bar, or 43.5 psi, and it is still a common pressure where injector flow is rated, but, the manufacturer can manipulate fuel delivery by simply changing the fuel pressure within a small range. This allows a single injector to cover a wider range of engine sizes and demand by changing the fuel pressure. Later model engines tend to run higher pressures, in the 50-55 psi range or so. This is not so much for greater delivery, but the higher pressure aids atomization of the fuel (up to a point). High base fuel pressure does not work well on a forced induction engine as the fuel pressure should increase with boost and there is an upper limit where the injector flow becomes unstable at too high a pressure, usually around 65-70 psi for common injectors.

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If they're just a little dirty, would using a good in-tank injector cleaner do the same job? Heck, wouldn't just driving it clear them out? The Shell V-Power better do something good for the price I paid for it frown.gif. The cleaning technique you described makes sense and seems very effective though.

BTW, can I get a vacuum operated vacuum/boost dash gauge and connect it with that vacuum line I plugged off? I like the look of a boost gauge and would probably be handy at some point in tuning

sc37.jpg

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I bought a fuel pump today. Work's gonna be delayed, since I leave on Thursday and don't get back until Sunday for the BPA state conference (me and a classmate from career center are kicking but in PC repair and IT concepts).

I think we're pulling out of this Michigan winter, so it's gonna soon be time to get my insurance from my Explorer transferred to the Reatta.

I need to reread posts from you guys (2seater's in particular) and do more testing. Haven't been able to think right about this from school and stuff

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I think I remember you said the MAF sensor is the same on the S/C as on the LN3 engine parts you removed, right? In other words, this is the same two piece assembly as the LN3? The reason I ask, is I noticed something during the MAF flow testing I have been doing. I mentioned I have a TPI manifold from a '91 engine. The MAF and throttle body are in a single integrated housing. There are two differences internally and that is why I ask. There is a passage inside that appears to allow air into the engine for the PCV system, and I don't know where that passage could exist with the stock style LN3 MAF/throttle body, there doesn't appear to be room for it. The s/c manifold has the same integrated PCV system as the TPI manifold does. I know you used the correct gaskets for the s/c manifold, so that passage should be blocked off, and not cause a problem. If the MAF is the same style that is a single piece with the throttle body, the sensor itself is different. If the donor engine did not come with the actual sensor, the LN3 sensor will bolt on fine, but it will not seal correctly. The sensor wires will be in the correct location inside the passage, but the passage is not a true round tube like the LN3 MAF housing. It has a larger cross section in part of it and the correct sensor has a tubular surround over the sensor wires so when it is inserted it completes the circular cross section passage. The location of the O-ring, and the size are also different, so it will leak vacuum also. I know this may not be a problem and everything is as it should be, but a bad MAF signal will cause all sorts of driveabilty problems. It may even run better with it disconnected, although not as it should.

One last thing, I noted during the air flow testing of the various style MAF's that the MAF/throttle body from the TPI manifold flows no more air than the stock LN3 setup. It looks more efficient, but the frequency response is the same, the flow rates are the same at the same frequency and it causes exactly the same amount of resistance to flow (depression). If the flow and sensor readings are placed side by side with the other five 3800 and 3300 sensors I tested, you couldn't pick it out.

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Will have a look as soon as I can. The part numbers are the same, but the single digit after the number is different. I assumed this is like a revision number and not a big deal.

As Ryan suggested, I tried running the car with the MAF disconnected, but it didn't help any. Didn't seem to hurt it though.

I'm using the MAF that came with the L67...haven't removed it or anything. Should I swap it with a known good one?

You guys give a lot of good info. I'm gonna owe you guys some drinks when the Lansing Reatta homecoming comes around

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I would bet the sensor in the S/C MAF is the same style as the TPI one I mentioned. I looked at the photos you have provided and the inlet to the S/C with the throttle body removed looks exactly like the inlet to the TPI manifold. That about 1/2" diameter hole to the rear of the throttle passage is the air inlet hole to the PCV system. All six of the MAF sensors I have are marked AFH50M, but they have three different suffix's -02A, -02C and -02E. All have different four digit numbers below. The TPI sensor is included in the six I have and it is one of the -02C sensors. The only external difference in the markings is the set of lower numbers is A1304 on the TPI sensor. My guess is the electronics is the same but the "A" prefix indicates a different internal construction for sealing and around the wires as I mentioned before. The only way to know for sure is to pull the sensor and see if it has the same consruction as the LN3. If it is the same, either the MAF passage is different than the TPI style I think it is, or, the sensor is the wrong one. I have included an attachment of the two sensors, the LN3 sensor on the left.

post-31580-14313788693_thumb.jpg

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I'm back folks. After a long, long weekend and plenty of chat about the Reatta, I have this...

national1.jpg

Through the Capital Area Career Center I attend during half of my high school day to gain A+ computer repair certification, I'm with the Business Professionals of America chapter. Google it up. We encourage "professionalism" (hard to explain). I'm of Michigan's region 9.

History: a few months ago, at the regional conference, I scored 1st place in Info Tech Concepts and 3rd place in PC servicing/repair. Doug, in my A+ class, got 2nd in PCs. The top 5 get to go to the State conference.

Which happened this weekend (which is why I haven't any progress to report on my car). The BPA put us (about a dozen, plus our 2 advisors) up in the Amway Grand Plaza hotel in Grand Rapids for 3 nights. It's an old school 4 star hotel. There's too much to say about how cool it was. Doug and I were in it to take IT Concepts and PC repair (written, multiple choice tests). Others of the Career Center were in it for group presentation skills and advanced interview skills (BPA is mostly about that stuff). There were over 2k students from all over the state there for various events.

I pulled out of PC servicing in 3rd place. Meaning, I'm off to the National conference in Orlando! It's a great deal. The state and national conferences are pretty much all paid for us. Top 5 in every event, from every state, are gonna be here.

Sorry if I got a bit too technical in The GPS Thread...

At any rate, I've got till May, so work will resume on my beloved car. The task at hand is to replace the fuel pump and the oxygen sensor (I already have it, so why not). Will do it early this week.

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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!

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Ha thank you.

As 2seater suggested, I replaced my oxygen sensor with a system reset...seems to be running the same.

I played around with it a little more, and if applied slowly, I can run up to 4200+ rpm (in neutrel). But still, any stab or reasonable application of the throttle will get it to choke/hesitate. Under normal loads, you really can't get any good acceleration. Hard to maintain speed going up gently sloped hills at 55 mph.

Gonna go on and do the fuel pump this week.

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Congratulations! Knew you were smart, just by what you have accomplished sort of "seat o' the pants". I think the TV cable connection you are looking for might just unbolt from the original LN3 throttle and could be transferred to the L67 t/b? The TPI throttle body I have looks to have the same linkage and connections as the LN3, including the little arm for the TV cable. It appears to be retained by a single nut and appears to be a discrete part that can be removed. The reason I say this is the '91 Buick would likely have the "E" transmission, but this t/b came from a Pontiac and they retained the mechanical transaxle for a couple of years beyond some Buicks. I would doubt GM used a dedicated throttle body for each of them.

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Thanks 2seater.

I'll investigate the cable further. What is it for exactly? I found the square hole in the LN3's "throttle body plate" but not in the L67's plate. With my glance, the linkage on the L67's throttle body doesn't provide for where the cable would connect to it, but I'll compare it with my LN3 throttle body and see if it can be swapped over.

And will post photos of the MAF, if there's anything interesting to see

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Today I bought my own fuel pressure gauge and a new Bosch oxygen sensor. Now, I can get my own readings whenever I please.

During the 1st two seconds with key on, engine off, I read 40 psi. Then, it drops to 38. Within 5 minutes, it drops to 30 psi.

Is this normal, or a sign of an injector stuck open? I'm still going to get a new pump (Ryan suggests one for a '89 Turbo Trans Am) and mess with that, but wanted to give you these readings and let you guys know that I have my own gauge and can check it whenever you think it should be.

After installing the new oxygen sensor, should I go ahead and start the car and report back new ECM readings? Thank you guys so much for all the help and advice on this project. A big, complex, expensive puzzle. And sometimes, you need to make your own peices. Or make some pieces fit. But we'll figure it out smile.gif </div></div>

I wouldn't go jumping in and replacing a fuel pump yet, check your readings first. Not that a higher output pump would be bad, but you may not need it.

Don't worry about the O2 sensor at this time, in fact you could unplug it for the testing phase. Clear the codes by unhooking the battery (or BLM reset function on a scan tool). This will prevent the ECM from performing fuel correction until you get everything else right. With the O2 unplugged, the ECM should show a reading ~450mV. This will set an SES, but won't be a problem for testing.

Try gapping your spark plugs to .025" and see if that helps. DIS is a somewhat weak ignition system and with the boost you've added can easily flame out, especially if you're running a bit lean.

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Yes, the L67 throttle linkages use the two cables. One's for the pedal and the other's the cruise control. However, the LN3 uses a 3rd cable that runs to the top of the transmission. It's a pretty short cable. I checked on our regular LN3 cars again and the black plate that's used do use this cable. I just need to figure out how to attached it to the linkages using the old plate. The L67 linkages don't have a provision for this cable. </div></div>

You definately want the TV cable. This controls transmission shifting and pressure. Avoid driving it much until it's connected and properly adjusted.

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sc39.jpg

Above are the two MAF sensors. The L67 has the extra black plastic surrounding the wires. I installed the normal LN3 one, which is known to be good. Below are my ECM readings for today, engine near operating temperature, MAF connected, but as Trofeo suggested, oxygen sensor disconnected. RPMs at 1500-1650 RPM...

ED01: .56

ED06: 3.9-4

ED07: .45 (expected from what Trofeo said)

ED08: 28 degrees

ED10: 0 degrees

ED17: 315

ED18: 16-22

ED19: 128

ED20: 158

ED21: 8.5-9.1

ED23: 6 degrees

ED98: 1

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Now, at idle. 750-775 RPM...

ED01: .48 (TPS from L67, with non-oval holes is being used).

ED06: 4.1-4.3

ED07: all over the place tongue.gif as oxygen sensors are

ED08: 18 degrees

ED16: 0 degrees

ED17: 518

ED18: 0-9

ED19: 130-139

ED20: 170

ED21: 4.3-4.5

ED22: 54

ED23: 40 degrees

ED98:0

After changing the MAF, I did connect the battery and discharged the system to reset the ECM. I also took fuel pressure readings. At idle, we're doing 32 PSI.

With easy application of the throttle, I've been able to get to 4200+ RPM. Never did think redlining without load was a good thing, but we've still got some room. At this speed, I'm reading 38 PSI. With a little jab at the throttle, it'll quickly jump up to around 40 and then come back down as the engine bogs out. The pressure slowly rises as throttle is applied (from idle and 32 PSI to near WOT, 38 PSI).

Is there anything I should do special in my testing and when gathering readings? I'm still not quite understanding my ECM data and how it comes together, but I'm learning.

Trofeo: I didn't get to it today, but would you still suggest that I change the plug gapping?

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With ED-20 at 170 the engine is trying to add max fuel. What is ED04 (coolant temp reading). If BLM is staying that high and the engine is bogging, it sounds like it is going waay rich but if you are getting crosscounts, the mixture is rite.

With no load, the engine should not bog. Is the tailpipe black and sooty ?

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The coolant temp was around 180 F, which is what my thermostat is, and Ryan programmed the fans to come on at the right times for it (and they're working).

I just went outside again to check on the smoke. I ran a finger on the inside of the outlet and I'd say that there isn't an abnormal amount of carbon or whatever it is. Never did it this kind of thing before, so I ran another finger in the tailpipe of the Select 60 and Claret (both known good running cars) and came out about the same. In my testing, I didn't stand behind the vehicle to check, but I didn't notice any black smoke.

Padgett: do you suppose you could explain the crosscounts again? I remember the BLM...below 128 is on the lean side, 128 is optimal, and over 128 is rich...um, right?

Thank you

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I wonder if you try a stock PROM if it will rev? don't run it long but just to see if the car will rev to check if it is the PROM causing the car to bog or it is a seperate issue. you could even use a 90 PROM to see or the 91 PROM would be good to because of the larger injectors the series one uses. I would try the prom out of the 91 and see if the car still bogs.

correct me if this is a bad idea, but I am wondering if the PROM is not allowing this car to run correctly and Ryan over did the fuel for the car.

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Well, I suppose that's possible with me running rich. Won't do anything quite yet, but I have a '90 Lesabre memcal (which ran my Reatta in stock form perfectly fine, but instrumentation was impaired) and a '91 Reatta memcal (currently in ECM).

I have the Lesabre memcal cuz last year we had some work done on my car...they replaced the ECM with the lesabre's but the dumbasses didn't bother to glance at the instrument panel and ECC. As Padgett suggested, I swapped my old memcal into the "new" ECM and everything went back to normal.

I have the '91 ECM because before this, we were going to have Ryan do a series II L67 swap and the ECM was going to be needed.

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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?

Don't try to use the LN3 MAF sensor in this engine. I reprogrammed your chip to work with the L67 MAF sensor, which is calibrated differently.

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.

What were the O2 sensor readings just before it started missing? How about when it was missing?

Could you provide me with the actual names for the data points listed "EDxx"?

-ryan</span>

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Got yet another reply from him. I resent my readings, for he requested that I lable the EDxx codes

<span style="font-weight: bold">It looks like the INT and BLM counts are high, which means the ECM is trying to add fuel for a lean condition.</span>

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Wow, there are so many good questions in this thread. Lets see if I can help out...

For the boost gauge hookup, you don't need to tap and drill anything on the lower intake manifold, at least not with this intake. That black vacuum block that sticks out of the top-front of the SC does "see" boost. The fuel pressure regulator and boost bypass solenoid should already be connected to this block. You can connect a boost gauge here.

As far as the MAF's are concerned, the LN3 and L67 units are definitely calibrated differently. I have reprogrammed Philip's chip to work with the L67 MAF sensor.

Plug gap on stock L67 engines is 0.060" using platinum plugs. If one were using copper plugs, I suggest a gap of 0.050" as a starting point.

Fuel pumps and pressure. I don't have the base fuel pressure specs for the Series 1 L67 right off hand, but I do know without the vac line plugged into the regulator and the engine running the pressure should be about 40-45psi. With boost pressure, the fuel pressure should rise 1psi for every 1psi of boost. If it is not, or the fuel pressure actually drops under boost, then the stock fuel system is not keeping up with the fuel demands of the engine. Which brings me to my next point.

Stock, naturally aspirated fuel pumps are designed to supply an adequate amount of fuel for the engines they are designed to work with; usually up to 45psi. However, at higher pressures these same pumps cannot supply the required fuel flow volume boosted engines demand which is why I suggested Philip install a pump designed for "boost duty".

-ryan

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So...should I get a pressure reading with the regulator vacuum line disconnected?

Keep in mind, that with RPM, it's indeed rising (idle:32 psi, 4000+ rpm: 38)

I don't know the stock LN3 gapping at the moment, though my plugs are fairly new and were gapped when I put them in. Should I change them to the 0.060''?

Ryan: would you like to use the board or email for communication?

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Ryan: would you like to use the board or email for communication? </div></div>

Hey, if the two of you don't mind, please do use the board. Although some of this is above my gray head, it is great gear-head stuff! Better than any of those reality TV shows! We're rootin' for ya. ROCK ON smile.gif>

cool.gif

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