ihscout54 Posted September 4, 2015 Share Posted September 4, 2015 IIRC there is a ground lug bolted right next to the thermostat housing kinda under the upper radiator hose that has given me greif in the past. 1 Link to comment Share on other sites More sharing options...
ihscout54 Posted September 4, 2015 Share Posted September 4, 2015 Oh, and Im at a loss for your code 55. If your spec code says your car is a fed emissions model, that DTC shouldnt be on the table... I doubt that it has anything to do with this. But an engine that doesnt match the ecm, throw in a corroded ground or 2, who knows. Are you absolutely sure your reading the spec code and DTC right? Link to comment Share on other sites More sharing options...
jetpilotdc10 Posted September 5, 2015 Author Share Posted September 5, 2015 PCV was a little dirty but is allowing for 19hg of vacuum. I've inspected every vacuum hose and they look good, but I suppose could connect a vacuum gauge to each one and see if there's a difference anywhere. Link to comment Share on other sites More sharing options...
jetpilotdc10 Posted September 5, 2015 Author Share Posted September 5, 2015 I'm 99% sure I'm reading it right. Maybe swap my ECU from my 92 parts car? Can that do damage in anyway? Link to comment Share on other sites More sharing options...
ihscout54 Posted September 5, 2015 Share Posted September 5, 2015 I'm 99% sure I'm reading it right. Maybe swap my ECU from my 92 parts car? Can that do damage in anyway? How could it? Easy enough to do. If its giving you nutty codes maybe its nutty too. 1 Link to comment Share on other sites More sharing options...
jetpilotdc10 Posted September 5, 2015 Author Share Posted September 5, 2015 This whole damn situation is nutty!! haha Link to comment Share on other sites More sharing options...
jetpilotdc10 Posted September 5, 2015 Author Share Posted September 5, 2015 What are the odds that my o2 sensor is bad, but not giving a code? It obviously has a direct influence on fuel mixture. This sensor looks like its been in there a while, and its the only sensor I haven't tested. Throttle, coolant, and MAF sensors have all been tested as per the FSM. Link to comment Share on other sites More sharing options...
ihscout54 Posted September 5, 2015 Share Posted September 5, 2015 The O2S is sorta a fine tuning device, and has no bearing on the mixture when the car is cold. Again you could unplug to test, but IMO its unlikely. This has kinda droned on, so we should regroup. Please let me know the status of the following: Fuel pressure, have you tested it under load, with your symptoms this is very important. Im wondering about the pressure regulator. Recheck your timing, Have you checked that ground Ive mentioned, yet? My advice done just look at them disassemble and clean em. Have you disconnected and plugged the egr and evap systems, yet? Overall engine condition? compression timing belts etc. it would be a shame to beat yourself over this and have a slipped timing belt or bad valve. Were the vac readings at idle pretty steady? Link to comment Share on other sites More sharing options...
jetpilotdc10 Posted September 5, 2015 Author Share Posted September 5, 2015 Regroup, great idea! I just spoke with the previous owner. He doesn't recall having a CEL (so no code 55) the last time he drove it, 2 years ago. He's not sure if the car is originally from Cali, but he's pretty sure its not the original motor. Fuel pressure is a steady 23-ish psi at all throttle settings. I have yet to test it under load. Fuel pressure regulator, pump and filter have been swapped with no change in performance of the fuel system. I noticed a broken wire on the sending unit, but the fuel gauge still works. Timing has been double checked @ 20 btdc with green connector connected. Also swapped distributor & coil, and replaced cap, rotor, wires and plugs. No change. When I got the car, the #2 camshaft was 180 backwards. I reset the belts very carefully and they appeared to be fairly new. I have yet to plug the EGR, but I did test it with vacuum and it stalled....pretty sure that's a pass. PCV was cleaned and provided 19hg of suction at idle. Vacuum was steady at 19hg at all throttle settings. I've cleaned and/or repaired all grounds under the hood that I could find.....drivers side valve cover, t-stat housing, and the big one near the starter. I applied a very thin coating of dielectric grease to all ground terminals. I think I'll start today with an ECU swap, followed by fuel pressure test under load and a compression check. I'm about ready to give up, but it would be a shame as the car is fantastic condition! 9/10, no rust at all! Link to comment Share on other sites More sharing options...
ihscout54 Posted September 5, 2015 Share Posted September 5, 2015 I have yet to plug the EGR, but I did test it with vacuum and it stalled....pretty sure that's a pass. On off function isnt all we want to see. Say the spring is weak, the orifice is enlarged, or its sticking. We can still eliminate the possibility of excessive flow. In this case it would smooth out under hard accel (IF its not sticking). Fuel pressure is a steady 23-ish psi at all throttle settings. This is a good sign, but if you have a voltage drop situation at the pump, or restriction in the line, when the regulator opens up the pump may not deliver. I think I'll start today with an ECU swap, followed by fuel pressure test under load and a compression check Good, plan. If neither yields results I have a couple other odd balls to check for. I dont want to confuse you or make you jump around so wait on these... First; voltage at the coil should be checked. Condition of the coil bracket ground, and Ignition Amp as well. Maybe your getting some weakness in spark. You should check the harness for frays or corrosion at the connectors. Especially the big connectors under the hood and the ones at the ECM. Check your fusible links and connections for corrosion. 1 Link to comment Share on other sites More sharing options...
ihscout54 Posted September 5, 2015 Share Posted September 5, 2015 I'm about ready to give up, but it would be a shame as the car is fantastic condition! 9/10, no rust at all! You seem to have access to an array of tools and testing gizmos. Your savvy enough to use them and seem familiar with general procedures and these cars. I think you can get this licked or at least diagnosed. 1 Link to comment Share on other sites More sharing options...
jetpilotdc10 Posted September 6, 2015 Author Share Posted September 6, 2015 I really appreciate your vote of confidence and all your help. I'm taking a mental health break and will resume work in a day or two. Link to comment Share on other sites More sharing options...
scoobiedubie Posted September 7, 2015 Share Posted September 7, 2015 1. Clean the MAF with specific MAF cleaning fluid from the auto store. Get every nook and cranny. 2. You failed to tell us how many miles on the vehicle. If you have over 200,000, then your main engine ground wire needs replacing, your fusible link wire to + battery terminal connection needs replacing and your alternator hot wire connector with some lead wire needs replacing. Link to comment Share on other sites More sharing options...
ihscout54 Posted September 7, 2015 Share Posted September 7, 2015 (edited) He brings up a good point... System voltage, or voltage at the ECM.Im not sure if you ever ended up adjusting the TPS correctly or what was the final decision on the injector condition.That code 55 is bugging me. It may have no bearing on youre drive-ability problems, but if the specification code is stating the car is a 49 state model then the ECM doesnt seem as though its functioning correctly. Or, not from what my older M/Y literature shows. In the trouble tree for that code it assumes you have a cali setup. One of the possible procedures in the tree shows if "x and y" are to spec, replace the control unit. From what youve stated about the car, I see no need (or way) to follow this tree. Im thinking process of elimination suggests ECM. You have another ECM on hand so that would be a good next step. Edited September 7, 2015 by ihscout54 Link to comment Share on other sites More sharing options...
Casull Posted September 8, 2015 Share Posted September 8, 2015 (edited) The 91 octane for sure is better. After having a 100% 91 filled tank now I can tell the difference in pickup and sound on the highway. HOWEVER, with my particular problem in the "rough acceleration" department I am noting that my car behaves as it should after getting my engine idle for a period of time. This may be different than your problem. See, it starts at a somewhat low, rough idle but eventually kicks into a very smooth idle (5+ minuets). Pickup is peppy thereafter, and the car is happy-- like, really, it's nice. But who wants to sit for so long waiting for a car to behave? I'll be having someone look at that in a couple weeks because my transmission main seal went out. That said, what if the problem is purely physical? I'd make sure those fluids are correct. I know, that's pretty basic to say. But my car sure did raise a brow when my ATF spewed. (Duh, dude, duh. I know. I know) Edited September 8, 2015 by Casull Link to comment Share on other sites More sharing options...
Natemanas Posted April 6, 2016 Share Posted April 6, 2016 What ever happened with this? Did you get the issue figured out? Link to comment Share on other sites More sharing options...
robm Posted April 7, 2016 Share Posted April 7, 2016 (edited) I dunno what is wrong with jetpilotdc10's machine, but Casull's problems are the classic symptoms of a failed CTS. The ECM thinks the engine is hot, so it gives it a mixture designed for a warm engine. Once the engine warms up, all is good. Edited April 7, 2016 by robm Link to comment Share on other sites More sharing options...
YnotDIY Posted May 11, 2018 Share Posted May 11, 2018 yo same issues over here. did this ever get solved? Link to comment Share on other sites More sharing options...
jkinz Posted May 11, 2018 Share Posted May 11, 2018 Very interesting thread, lots of good info. I have a similar problem to yours with my 87 SPFI and some other threads I've seen but not nearly as severe. Ever since I had the engine out for a head gasket, the thing doesn't like very much throttle at low rpm, and full throttle it will "fall flat on its face" as they say. I can drive around it which I have done, but the car doesn't have that scoot like it used to. Unless I rev n' dump the clutch and then I just get lots of tire spin from my crappy 185R13s... I've certainly not delved as deep as you into it but I did change out the entire exhaust system which was completely smashed and re-welded a million times and no change. basic tuneup fuel filter plugs cap rotor, no change. The plugs looked great and didn't really need to be changed after I think 20k miles or so. when I get the chance I have some extra MAF and TPS to swap (or I'll try to clean it). I swapped a different PCV valve, haven't looked at any of the other stuff and no ECU codes. I swapped in a used radiator at some point, can't remember if it coincided with this problem or if I've tested the CTS, might start with that. I probably need to set aside a whole day and follow these steps but that's never gonna happen... Such a frustrating problem and I feel your pain, this is why I've avoided it for so long "hoping" the engine would blow up at some point and force me to go EJ... but this is a runner got the car for $500 no rust with like 150k on the odo now its at 180k doing great after all the abuse Link to comment Share on other sites More sharing options...
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