Fuel Injector noid test question

[Guest Brolliar]

On a Reatta with the engine running can you disconnect the injector electric plug and plug in a noid to test the signal and then take off the noid and re-connect the injector and then move on to the next injector and do the same thing? Or will this harm something, ECM etc???

[padgett]

I don't think that would be a good idea but offhand think the circuit should be dsigned to handle opens.

[Guest Brolliar]

Padgett, thanks for your comments. It was after doing the noid test as I described that we thought the way we did it might not have been such a good idea. :confused: Were still chasing the miss I have talked about in an earlier post and it seems every time we try something the miss only gets worse. Tried a used Delco ignition monitor and coils and it just made the motor hard to start and also run poorly. Then went back to the magnavox and it still ran the same as with the Delco. Now cylinders 3 and 5 seem to provide almost no power to the engine. Think we will probably check out 3 and 5 injectors next. Maybe they are clogged.

[padgett]

Frankly I only expect a 50% good rate on junkyard parts, most will allow an exchange within 30 days. Might take both to AutoZone or a FLAPS with a tester and have tested.

[Ronnie]

Now cylinders 3 and 5 seem to provide almost no power to the engine. Think we will probably check out 3 and 5 injectors next. Maybe they are clogged.

Possibly head gasket blown between the cylinders? Have you checked compression?

[2seater]

On a Reatta with the engine running can you disconnect the injector electric plug and plug in a noid to test the signal and then take off the noid and re-connect the injector and then move on to the next injector and do the same thing? Or will this harm something, ECM etc???

Disconnecting injector shouldn't harm anything, you can manually turn them off via the onboard diagnostic overides. Possible the injector is stuck or plugged? It wouldn't make much difference even if getting the signal from the ECM. Do the plugs look substantially different in the affected cylinders? Can you hear a sharp click as the injector cycles? Even a large screwdriver touching the injector and held to the ear will help to see if they all sound the same.

[Guest Brolliar]

Got delayed for a couple of days working on other tasks.

Ronnie and 2seater I appreciate your help and comments. Turned out they were based on bad data that I provided for which I am Sorry. To continue we took off cylinders 1, 3 & 5 plugs to look at them. Padgett, since we had switched back to our original Magnavox module, thinking the Delco module had a problem, we re-gap the plugs to .045", as you had recommended for the Magnavox module on your Delco/Magnavox module comparison page padgettp.com . The 3 and 5 plugs did look bad, one gas covered and the other gas covered and black with soot. But in connecting the plug wires to the Magnavox module we noticed the 3 and 5 plug wires had been swapped. This must have been done by a gremlin as we slept . Or possibly the heat had addled our brains.

So, when the Reatta started up it ran great, just like it should. Of course the engine was cool but no miss occurred even as it warmed up some and went closed loop, per the CRT. It was cooler weather following a rain and with the air con off since the compressor clutch had died during engine testing and the water temp only went to 190 degrees. It had been 200 -210 degrees when the miss occurred. It should be warmer today so we will see if changing the plug gap corrected the problem. I will follow this post up when we get hot engine results.

Thanks again for all the help.

[padgett]

It is really astounding how well the ECM can compensate for even two plugs being swapped, is now one of the first things checked for a miss if someone else worked on it . Some are even easy to get wrong at the plug if not really careful. Too bad they are not color coded.

[Guest Brolliar]

Re-installed the Delco ignition monitor. Also put some injector cleaner in the gas tank. Last night drove the car and it ran great for a 20 mile loop including stopping at stop lights. Then pulled it in the garage with engine running and as it sat there it started to miss as the rpm was raised above an idle. As if it is some sort of heat soak problem?? Also Padgett you previously asked about ED17, the knock sensor activity. Last night it was 309 and this morning it was 166. Not sure just what these numbers mean. The only error codes are B552 and C553 which both seemed to be related to the battery cable being disconnected. It was dis-connected when the BCM was changed out.

[Ronnie]

Have you cleaned or Replaced the MAF sensor?

[Guest Brolliar]

Ronnie, no I have not done either.

[padgett]

The knock sensor is a count of how many times knock was detected and the spark was retarded. Need to keep it displayed and see if it is incrementing while the miss is happening.

Zeros on every start. Coupla hundred on startup or a few on sudden acceleration is OK. Incrementing at idle or below 1500 steady is not.

[Ronnie]

Sometimes tapping the MAF lightly with a plastic hammer (or screwdriver handle) will give some idea if the MAF is a problem. If the engine stumbles when you tap the MAF you can be pretty certain you need to investigate further. However, if it doesn't stumble it doesn't necessarily mean the MAF is good. Just a quick and easy first test.

[Guest Brolliar]

Ronnie & Padgett, thanks for the info. We will try some light tapping (now that I found the MAF location in the manual) and will watch ED17 and see what does before and during the miss.

[padgett]

BTW, tapping might trigger the knock sensor depending how hard. Tapping a screwdriver butt on a valve cover will.

[Ronnie]

BTW, tapping might trigger the knock sensor depending how hard. Tapping a screwdriver butt on a valve cover will.

I agree but I wouldn't think the knock sensor being triggered, resulting in slight timing retard, would result in a miss that the driver could feel. At least I have not observed that.

He said his symptom was: "started to miss as the rpm was raised above an idle". Under normal operation the knock sensor works in the background without the driver perceiving any change in the operation of the engine, with the exception maybe of a slight loss in power by a driver keenly in tune with his engine. I have never felt a miss that I contrubuted to the normal operation of the spark knock sensor. I guess it is possible...

[padgett]

Just eliminating things. Maybe a snapshot during normal and missing op?

[Guest Brolliar]

Padgett, snapshots do sounds useful. First have to read up in manual on how to take a snapshot.

[padgett]

Once you have access, download the 88 Diagnostic manual from reatta.net. It tells all.

[Ronnie]

In the meantime, while you are waiting on reatta.net, you can read about diagnostics. Page 7 tells how to take snapshots.

Computer Diagnostic Instructions - 1988/1989*-*ReattaOwner.com

[Guest Brolliar]

Padgett, thanks for telling me about the 88 Diagnostic Manual. I was looking at the 89 Service Manual. Have the Diagnostic Manual now. Ronnie,Pg. 7 does look like the important page.

We are talking about the ECM diagnostics, right? What would we take snapshots of Data, Inputs, Outputs??? I think we can take 3 snapshots. Got to figure out how to recover them after taking more than one.

[padgett]

I'd be mainly interested in the data points, looking for a difference.

[Guest Brolliar]

So were talking about the ECM Data points, without the miss and with the miss.

A little more about the miss. It seems to be a little less pronounced. Following 20 miles of driving there is no miss until you stop outside your garage and let the engine compartment heat soak a little bit then at idle it is gone and when accelerating it is gone. But it is there under light throttle.

We will check the snapshot data points without the miss and with the miss and see what we can learn.

The compressor and accumulator came in today from Techchoiceparts.com. More reading and then a choice of who will replace it, us or someone more experienced. The a/c did go out in a rather odd manner one minute driving and the a/c blowing cool air and the next smoke coming out from under the hood, the clutch all messed up and a line of oil in the plane of the clutch/compressor connection.

[padgett]

A/C failure is typical of a frozen compressor, smoke was probably from the serpentine belt. Whether simple or complex depends a lot on what the orifice tube looks like. If crud is present then the system should be flushed.

Always change the orifice tube (is only a dollar or two unless you spring for a variable).

If R-12 then this is a good time to convert to R-134a unless you have a supply of R-12 and if converting, flush.

Think there has been some discussions about mineral oil (R12) vs PAG (R134) and POE (both) there are points to be made for both sides but you really do not want to mix mineral oil with R-134a

[Guest Brolliar]

Padgett, we did get the orifice tube and thanks for the A/C R-12 vs R-134a and the mineral oil vs PAG comments.

Also Padgett, at last we finally got the ECM Data. Sorry we were so slow in getting it.

The first set of tests run in the afternoon are in the left thumbnail. The test condition is described on the upper line of the spread sheet. For columns C,D,E, and F there is no engine miss. In column G the engine speed is increases until the miss just starts. The ignition cycle counter at the bottom increases by one each time the car was restarted. All these tests are with the Reatta stopped. The temperatures given are in Celsius. The car seemed to be running better and more heat soak and a higher rpm was required to get the miss to start. The oxygen sensor data seemed quite low on three of the tests after the heat soak??

The right thumbnail was later that afternoon Columns D thru G were after some acceleration runs. During these tests the car started running worse with some low oxygen sensor data in F & G and the knock sensor going wild in D thru G.

All comments would be appreciated.

Edited August 5, 2010 by Brolliar
Provide a cleared and hopefully better description of the tests. (see edit history)

[padgett]

Interesting that the knock signals are going bananas but whether cause or effect I do not know. No codes are being set.

At 46 mph/1300 rpm you are in O/D lockup and the engine will be most demanding of ignition quality here. The fact that it heals when cold makes me incline towards an electrical issue.

To me this looks like a classic secondary ignition problem (ICM, coils, plug wires, plugs - any one could cause). What is bothering me is your mention of 3 & 5 doing little since they are on different coils (3-6 or 2-5 would make more sense). When it is running right does it feel like it has full power ?

Frankly I have lost track of what all you have tried. Perhaps a recap would help.

At this point I would put either an ignition tester on each coil or just swap the whole module with a known good one.

[Guest Brolliar]

Padgett, thanks for your comments.

A recap - The Reatta didn't miss when the engine was cold but starts missing when the engine gets warmed up missing at low rpms under load first and later also at idle. First replaced the plugs and then put on a autozone ECM with no improvement. Then installed Bosch 8mm plug wires and got a loaner noid kit. After a rain and lower air temp the car ran like new with no problems. The noid also said the injectors were getting a good electrical signal. As the heat went up the miss came back. We then put in a new Duralast ICM under the old magnavox coil pack and the miss changed in character but did not go away. We also gapped the plugs at .045". Then got a used Delco ignition module and coils from Jim Finn and it improved things a little. Checked the coils and all three measured the same. By now the idle miss even when warm was gone. The car changes from open loop to closed loop fairly quickly with air temp in 90's and the miss doesn't start until you drive it stop and go for 20 miles with no miss. Then park it in the garage a little and let it heat soak and the miss comes back when above an idle.

Then ran a few acceleration run thinking it might help some. But the car started running very bad giving the second set of EMC Data. Since it was running so bad we took the ERG off after stopping the engine and took the picture below. On the lower left it looks like a solenoid isn't centered. Not sure of what to make of this.

[padgett]

Need to check what mine is running for Air flow, IAC, and pulse width at hot idle. I would expect one to be different when missing.

Do know a leaking EGR could affect idle but shouldn't when driving at 46 mph.

[Ronnie]

Can you fabricate a block off plate for the egr and try running it without the egr to see if the problem persists? Yes the ECM will complain with codes and warnings but the running should be consistent and that would tell you if the egr is the problem.

[Guest Brolliar]

My son is planning to disassemble the EGR, clean it and see if a solenoid is misaligned. Currently it is raining at his house which will cool things off some. I will post any interesting results. Making a blocking plate would be a little harder.

[2seater]

My son is planning to disassemble the EGR, clean it and see if a solenoid is misaligned. Currently it is raining at his house which will cool things off some. I will post any interesting results. Making a blocking plate would be a little harder.

The holes for the various EGR passages for the solenoids are quite a bit smaller than the base plate so alignment isn't critical. The round plate on the bottom of the solenoid is also larger than the passageway it controls so that shouldn't be a problem either unless something is defective. It is possible that the plunger could be sticky but is easy to check. EGR delivery is also dependant upon the gear the transmission is in, somewhat intertwined with the low rpm and lockup under 50 mph, where ignition strength is critical.

[padgett]

Checked the settings on my 88 after 5 miles & at 183F (83C). Do you have a 180 thermostat several readings were below 195/92C ?

Mine: at 725 rpm idle - I note your idle is fast, stock is 650 rpm hot, have adjusted mine up to help a/c.

Pulse width 5.0

Advance 20 degrees

Knock 502 from cold start and stable

Air Flow 4.8

IAC 39

Integrator 135

BLM 139 (slightly off idle, is 155 at idle)

Almost sounds like your throttle plate is not closing fully: would account for the fast idle and increased MAF reading though TPS looks good. Excess EGR "should" resullt in a lean mixture and I would expect the Int and BLM to kick up to compensate. Of course all could be the effect of the computer trying to compensate for the miss.

[Guest Brolliar]

2seater, thanks for your comments and Padgett thanks for your data for comparison.

We cleaned the EGR, and from the rub and shiney spots decided the one solenoid being mis-centered was probably just because the engine was running very badly when it was stopped. Each soleniod has a swivle pintle that lifts to open the passage which helps with the alignment. Also considered Padgett's comment about EGR shouldn't affect it at 46mph. And since it looked fine we reinstalled the EGR. The Reatta ran great after the reassembly which pleased us since it was running so bad when it was stopped. Drove it for normal Saturday shopping and it alternated between running great and a slight miss, running fine most of the time. The miss seems to come at random but then during continued driving it will go away. It is a little cooler this morning. It was more likely to miss after a hot soak, like at a store, but will go away after driving a bit.

Padgett, we weren't clear about the idle data. It was with the car in neutral. In drive the car idles at 650 rpm with occasional varriations to 675 or 625. I'm not sure which thermostat it has 180 or 195.

We plan to replace the fuel filter. Possibly that will help the miss some.

Thanks to all for your help.