RyanCooper Posted August 1, 2021 Share Posted August 1, 2021 So me and a friend purchased a 1988 Buick Reatta with about 169k miles on it (IIRC) and we've been trying to run down a strange misfire. first it would do it all the time, now it idles fine, but doesn't run super smooth under light throttle (slight cutting out) and will act as if its running on 3 cylinders when you go past say 1/4 throttle and beyond. does it worse in OD with the TC locked but will do it in park or neutral as well. the car was last tagged in 2017 i believe. we replaced the plugs, wires, air filter, fuel filter, and the injectors, we also noticed the cat was clogged (especially apparent when we ran some berryman through the intake (like seafoam)), so we removed it though it didn't look as bad as i expected, taking it off helped a little but not much. only things i can think of are: ignition coil pack, ignition control module, map sensor, dirty or bad MAF, cam position sensor (if these had those?) or maybe a failing crank sensor (though from what i know those will cause a crank no start but i could be wrong) any help would be appreciated. Link to comment Share on other sites More sharing options...
DAVES89 Posted August 1, 2021 Share Posted August 1, 2021 I would do the Ignition Control Module/Coil Pack. 2 1 Link to comment Share on other sites More sharing options...
Padgett Posted August 1, 2021 Share Posted August 1, 2021 If no codes it could be anything weak in secondary ignition (ICM, coils, plug wires, plugs. I'd switch to a Delco ignition, quality 8mm plug wires, and Delco Rapidfire (platinum) or Iridium plugs. 2 Link to comment Share on other sites More sharing options...
Ronnie Posted August 1, 2021 Share Posted August 1, 2021 Welcome to the forum Ryan. You have already got some good advice. I would like to add that checking fuel pressure would also be a good idea if you haven't done so. Complete instructions for testing pressure and pump performance are in teh How-to guides here on ROJ. 1 Link to comment Share on other sites More sharing options...
Nailhed66 Posted August 2, 2021 Share Posted August 2, 2021 No mention of if you’ve checked the CRT computer for codes. If the touchscreen is working, that will help narrow the issue. I sympathize completely as my ‘88 is currently operating in limp home mode which happens when the ECM is not getting a good signal from the ICM. The car is only running on 4 cylinders and is not happy. It could be as simple as a bad wire or connector in my case. Link to comment Share on other sites More sharing options...
RyanCooper Posted August 2, 2021 Topic Author Share Posted August 2, 2021 CRT is working and shows nothing for the engine (just for the AC freon level) and no CEL (though the dash gauges have been inconsistently working at all lately). I forgot to mention we checked fuel pressure, it went up to 47psi at prime at settled at 42psi. i pulled the vacuum hose off the FPR and no fuel came out so i presume thats working properly. removed the coil pack from the ICM and it was pretty gooey under there and leaking pretty bad which i read is a way to tell its bad (and it was a mess) The plug wires are new as well as the plugs, though they aren't of "OEM" AC Delco quality i figure they shouldn't cause any issues, given they made it idle a lot better after we did them. car looks like it had a lot of highway miles and very basic maintenance done. lots of things appear to be very old or original. checked lots of wiring to parts of the engine/sensors and the engine harness all appears to be just fine. Link to comment Share on other sites More sharing options...
Ronnie Posted August 2, 2021 Share Posted August 2, 2021 40 minutes ago, RyanCooper said: removed the coil pack from the ICM and it was pretty gooey under there and leaking pretty bad which i read is a way to tell its bad (and it was a mess) If you haven't changed the ICM you should. The goo is a good sign it is bad. Link to comment Share on other sites More sharing options...
RyanCooper Posted August 2, 2021 Topic Author Share Posted August 2, 2021 1 hour ago, Ronnie said: If you haven't changed the ICM you should. The goo is a good sign it is bad. That's what we're gonna try next. I assume the coil pack should also be replaced at the same time, definitely couldn't hurt since it too looks quite old etc. 1 1 Link to comment Share on other sites More sharing options...
Padgett Posted August 2, 2021 Share Posted August 2, 2021 (edited) "CRT is working and shows nothing for the engine " - do you know about the diagnostic capability ? Section 8D in the Service Manual. Worse under load is almost certainly ignition. "though the dash gauges have been inconsistently working at all lately" - is the jumper cover marked "do not remove" in place on the ALDL connector under the dash ? Edited August 2, 2021 by Padgett Link to comment Share on other sites More sharing options...
RyanCooper Posted August 2, 2021 Topic Author Share Posted August 2, 2021 1 hour ago, Padgett said: "CRT is working and shows nothing for the engine " - do you know about the diagnostic capability ? Section 8D in the Service Manual. Worse under load is almost certainly ignition. "though the dash gauges have been inconsistently working at all lately" - is the jumper cover marked "do not remove" in place on the ALDL connector under the dash ? I assumed when y'all say it will show codes on the CRT that it just shows diagnostics or warning info when something is wrong. the car doesn't have any manuals either so i can't say im super familiar with it. also couldn't tell you as i didn't know what to look for yet for it, they were working fine for the drive home in it and for about a week, then only the dummy lights worked, now nothing does but the CRT. the car of course has been sitting a while so i just assumed that had a major play in it. we were wanting to get the important (mechanical) side done first before moving on to electrical. also the blower motor at one point decided to randomly turn on and stay on so we unplugged it for now. only wiring i can see thats questionable is the hanging relays at the firewall, looks like they might've gotten hot or something, connectors and plastic all looks fine but the insulation looks a bit weird, no touching/crossed wires though. Link to comment Share on other sites More sharing options...
Ronnie Posted August 2, 2021 Share Posted August 2, 2021 8 minutes ago, RyanCooper said: couldn't tell you as i didn't know what to look for yet for it Click here and follow the instructions that will tell you how to enter the Reatta's onboard diagnostics. Write down any codes that are displayed. Be prepared to write down the codes. They will start being displayed as soon as you enter diagnostics. 2 Link to comment Share on other sites More sharing options...
Padgett Posted August 2, 2021 Share Posted August 2, 2021 and the rest of the story: 1) read and record codes (C)urrent are more important than (H)istory. 2) Clear all codes 3) See what (if anything) comes back. 1 Link to comment Share on other sites More sharing options...
RyanCooper Posted August 3, 2021 Topic Author Share Posted August 3, 2021 Update: the ICM and Coil pack did fix the issue, however it still has a light throttle misfire/hiccup but otherwise it has good power and responds to more load and throttle/rpm etc now and does so smoothly and cleanly. after we drove it back from a little wash it was hunting in idle (said CEL came on but we didn't get a chance to check the codes) but on the way out to the wash i pulled the codes and they were all history codes and were: E041, B448, B552, C553. i cleared the codes afterward so tomorrow when we get back to putting in a "test pipe" in place of the cat, and cleaning the interior ill try to check and see what code/s its throwing now. 1 Link to comment Share on other sites More sharing options...
DAVES89 Posted August 3, 2021 Share Posted August 3, 2021 Hopefully the codes stay history, but you may want to do the oxygen sensor as well as cleaning the idle air control as well as the idle air control housing. I use carb cleaner and an old tooth brush. The screws are stainless steel and if you drop them they are gone [however they are the same screw as what holds the MAF sensor in place]. Lay a rag under the idle air control housing to catch the screws... 1 Link to comment Share on other sites More sharing options...
Ron Walker Posted August 6, 2021 Share Posted August 6, 2021 My '89 CRT recently shows an E041 code (Cam Sensor Circuit), in addition to an E034 code (MAF Sensor Voltage Low). I'm changing out the MAF , but what is the cure for the Cam Sensor Circuit? Link to comment Share on other sites More sharing options...
DAVES89 Posted August 6, 2021 Share Posted August 6, 2021 There is a 'How to" tab at the top of the page. There is a lot of information there about an easier way to replace the cam magnet. 1 1 Link to comment Share on other sites More sharing options...
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