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Engine missing irregularly quite often.


Guest radiotradio

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Guest radiotradio

The 1990 reatta engine is missing quite regularly, but the problem also goes away while driving. It is difficult to determine when it is going act up, but it will remain missing for up to 10 minutes and exhibits lack of power until it clears. It seems to be the front passenger side cylinder at first, as all others, except this one, cause the engine to stumble when spark plug wire is removed from the coil block. I have not yet confirmed it is still this cylinder after the spark plug, injector (new from ebay), and in-line fuel filter have been changed as it seems to be OK at this point. It won't last, as it did act up after the parts were changed. I have not measured the fuel rail pressure for lack of a proper schrader valve adaptor. Reading earlier posts, makes me believe the next step is to measure the fuel pressure. Is an adaptor available so a tire guage can measure the fuel pressure? Does anyone have any hints that may help me get to the bottom of this problem. The spark plug wire has been ruled out. What else may cause this problem? Thanks! jack <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" />

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Guest imported_blazer1997

Congratulations you have joined my club. 3 months later, and everything replace from gas tank to ecm, prom every gasket,sensor over $800.00 in gm parts still have same problem as you. Stay in touch if find your problem. Thanks

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Check/clean the area under the ICM, (ignition control module-coils are mounted to it), water bearing debris can cause the ground there to become intermittent.

Check the individual coil pack for the suspect cylinder.

Check/replace spark plugs, these engines like good plugs and hate dirty ones.

Check the harmonic balancer pulley, for cracks in the rubber core, the crank sensor trigger wheel is part of the pulley.

GOTO Reatta.net and learn the process for reading the codes from the car's computer, this will enhance your diagnostic capabilities. ICM, coils, wires or plugs may not trigger a code, that's why I made the suggestions above.

Post a photo of your Reatta, for us all to enjoy!

Consider applying for membership to our exclusive auto club, BCA/Reatta division. I'm always happy to offer my BCA number to sponsor a new applicant.

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Guest radiotradio

Thanks for the help Randy, I took the coil pack off and it was a surprise to see just spade lugs hooking to the ICM. The potting compound was real sticky and the ICM had this number: 24503623 and 0345 painted on the sticky stuff. The upper right corner of the ICM had little balls about 1/16 of an inch in diamter. I read at one time that may indicate a problem in that the potting compound may have boiled or bubbled. I believe the engine in my 1990 is a Goodwrench rebuild. Maybe being done about 3 years ago, but I haven't confirmed that. The chassis has 140,000 miles on it. It has a GM factory rebuild sticker on the valve cover. I will explore the other items you mention. If I figure out how to attach a pix, I will soon. Thanks Jack

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Guest radiotradio

The coil Pac and ICM were replaced today, but the same thing occurs. I will be able to measure the fuel pressure on Monday. Bought a Magnavoix coil and ICM off a 1992 Bonneville yesterday for $40.00. I notice the idle changes as the fuel regulator vacuum line was removed. I think I figured out how to post a couple pix. I will keep this board informed of the progress on solving this problem. My engine is not just missing.....I think its lost. Help! jack reatta.jpg and reatta2.jpg

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Guest TommyH

nice pictures, but a bit on the big side. if you are using photobucket, select uploading options, and choose 15" screen or message board(620x480)

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Guest radiotradio

I do not hear any strange noises when it is acting up. I will be able to measure rail pressure tomorrow, but I'm beginning to think it may be somthing else, as it is the same number 1 cylinder that is acting up even after replacing the injector, sparkplug and sparkplug wire on that cylinder. It is the only cylinder that doesn't make the engine run worse when the individual sparkplug wires are removed from the coils. I sprayed a little carb cleaner around areas of the manifold gasket I could see, but it didn't change the rough idle. Could the manifold gasket be leaking and cause this problem? The problem comes and goes, but generally runs OK until it warms up, after which, it acts up when it feels like it. After all the parts others have been through, I hate to just throw more money at it. It looks like it is going home on a trailer this year as time is running short. Thanks for everyones help! jack PS: I have not measured the compression when it has been acting up. Is this something I should confirm being good?

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Guest imported_blazer1997

I changed my manifold gaskets, and every other gasket nothing changed the problem and still there.

Seems there are several owners having the same problem regardless of the year reatta they have.

Back in mid 60 I was a certified gm mechanic before going into lawinforcment, and have never had a

vehicle that i could eventually find the cause of a idle problem.

But with all the electronics, and relays this one has me acting stupid, and keeping my wallet dry.

Let you know if and when i find the problem if it can be found, and you do same.

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Guest radiotradio

It was the older style with all 6 coils in one pack. I saw a bunch of the separate packs, but none had the correct Reatta ICM connector. I went to a "you pull it" place and they told me to look for cars that the 8th letter of the vin number was a "C". It was the only one I could find among about 30 cars. I originally brought home a Delco pack only to find the connector was different so I went back to get the older style. I noticed some cars had the Coil Pac mounted behind the radiator on the front of the engine. The one I took off was a bear to get. jack <img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" />

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Guest radiotradio

Thanks for the offer, but I hate to even drive it that far. I'm thinking the ECM might not be sending the proper signal to the injector, but have no experience in that regard and no one has mentioned it. Sure wish I had another Reatta with good parts to swap out. jack

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All 3800s after 1988 use the same connector and module. Different engine families do use different keying for the connector. See my page for more than you ever wanted to know.

Too bad you cannot get here since I have a spare for just about everything and quite a bit of instrumentation but you might look at my prior posting on $100 of test gear.

I would suggest running a compression test on the front bank since easy to get to and the cyl you said had a problem is there.

The odd thing about a "waste spark" ignition like the Reatta is that if #1 is not firing, you need to check #4 as well but if #4 is firing then probably the ignition module and coilpack are good.

I suspect we need to forget about the electonics and run some old fashioned tests.

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Guest imported_blazer1997

I hate to say this but from my hard head, and empty wallet replacing everything suggested take it to

a Buick dealership. Not knocking any members here they are very intelligent, but seems several other

members have the exact problems we have and nothing suggested has changed the problem.

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Are you certain the new injector is actually working? Even without a noid light, you should be able to hear a steady tapping of the injector with almost any rigid material held to your ear. It would be unusual for it to stick part time, they work or they don't (generally). I have had cleaned injectors be stuck from sitting around. That shouldn't be a problem if it was brand new, but there are lots of remanufactured injectors in the pipeline. If you suspect a problem with the injector wiring or ECM signal, it may be beneficial to swap harness connections for adjacent injectors if the harness will allow it? It may not run as smoothly since the injector timing will be off, but it would give an idea if the problem follows the wiring. I have heard of injector wiring connected incorrectly causing a rough idle.

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Guest radiotradio

I am beginning to think Padgett is correct in saying forget the electronics and trouble shoot the engine. It is probably a sticky valve. I, to, do not want to take out a hot sparkplug for fear of striping the treads in the aluminum, so I am going to assume a stuck valve. By putting a can of transmission fluid in with my old oil and some in with the gas, this combination is suppose to unstick the valve stem. The fact that my problem always seems to be the same cylinder, I will try this old solution and see what happens. I'll run it for for a few days and then change the oil. My car had been sitting for a few years with out major use. I didn't measure the fuel rail pressure, but do plan to do so soon. This thing is not going to get the best of me. The number 4 cylinder is working properly, I even changed the 1 and 4 wires around knowing how the waste spark sytem works. Still have a smile at times! <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" /> jack

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Guest radiotradio

The oil was changed today and I used a quart of Risolene engine treatment oil with the change. It still is running bad, but I expect it may take a while to clean the engine. The fuel rail pressure was measured both when it was running good and bad. It was 35 pounds with the key on and dropped to 30 with the engine running. It goes up to about 36 pounds with the vacuum hose off the regulator. This seems low compared to other posts, but believe it is OK and not the problem. It remained the same in both circumstances. No E codes have been set. It still is the number one cylinder acting up. When it cools off, will measure the compression on that cylinder. It usually doesn't start acting up until the temperature reaches about 1/3 on the temp gauge (probably a good hint). The coolant temp is 91 degrees C at idle (ED04). The only three "E" codes that seem out of whack is the knock signal ED-17 at 1458 (should be 0-255), the Ignition cycle counter ED98 at 51 (should be 0-50) and the MEM-CAL Number ED99 at 8064 which should be 0-999. Don't know how to analyze these numbers. Still thinking it is an engine fault like compression, sticky valve or manifold leak and nothing to do with the computers or electronics, but still a newbie. HELP! It may take awhile, but we will prevail. <img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" /> jack

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As long as you're trying to clean things internally try some Seafoam. Suck it in the intake with a vac hose. Don't go too fast or let it kill the engine. Suck about half the can in. Let it sit for forty-five minutes. Start it up. It will generate an amazing amount of white smoke. You don't want to do it in your garage. It will clean up the insides pretty well.

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Some values are two bytes (16 bits) not one. The PROM ID is one of these. 8064 is correct for a stock Federal 1990 Reatta (2.97:1 axle) with the "cold-start" update.

At least a compression test on 1-3-5 is easy. I would swap the plugs around when re-installing.

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Guest radiotradio

Still acting up as temperature rises................thinking it is still a bad valve or gasket. Compression when running well is 130 pounds. May replace intake and head gaskets tomorrow. Bummed Out! No change from original problem after all the changes. Problem comes and goes after warming to 3/8-1/2 temp scale. jack

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Guest radiotradio

The ECM fixed the problem. It came from a 1990 LaSabre. Changed the MemCal EPROM and a couple of mounting screws from the orginal and it cured the missing number one cylinder. All in all, about $300.00 in parts fixed the entire car including the brakes. Without some help from this Forum, it would have been much harder to do these repairs. Don't worry about buying 20 year old technology......there seems to be a lot of parts around for the moment. Thanks for everyones help! jack <img src="http://forums.aaca.org/images/graemlins/laugh.gif" alt="" />

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