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Do ECU's ever go bad in these cars? We are troubleshooting and thinking it may be our "computer"?? Anybody have experience where replacing the engine control computer fixed their problem? Car is running bad and not cranking well either. Thanks -- James |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 89GTASC
(Post 5211300)
We are troubleshooting and thinking it may be our "computer"?? Anybody have experience where replacing the engine control computer fixed their problem? Car is running bad and not cranking well either. Thanks -- James |
Re: Do ECU's ever go bad in these cars?
Originally Posted by tunedperformanc
(Post 5211317)
By not cranking well are you trying to say it cranks over for a long time before it starts? or like it cranks hard like timing is too far advanced or a stater or battery issue? are you getting any communication with the ecm (check for codes) ? sounds like you are describing faulty injectors. car started acting up about 1.5 yr ago, it used to run well for 30 minutes, then act retarded like its missing hesitating, rough idles etc. let the car sit for 1-2 days, then it would run good again for 1st 30 minutes. it did this for months.... but now 1.5 yr later, we are trying to figure out what the problem is putting new parts like distributor w control module, plugs, wires, cap , rotor, fuel filter.... car did a lot of sitting, so don't know. we think maybe the computer, some thing called electronic spark control module, i thought maybe coolant temp sensor or air intake sensor since car never drove well under 60 degrees. but what you said faulty injectors, it very well could be... maybe i should try doing something about the injectors. More info: we can crank it by spraying quick start spray into the throttle body, and it will bust off, but still it runs poorly. so fuel injectors work, but yeah you could be right, maybe they could be faulty. When i say run poorly, its the old symptom when it used to run good for 1st thirty minutes, then starts to act retarted. I remember when i hit a bump in the road 1 time it started acted retarded, then i hit another bump and it went back to running well again. so that sorta doesnt sound like injectors to me, but like a loose wire or something.. |
Re: Do ECU's ever go bad in these cars? I did get back reply from brockscamaroandfirebird.com saying they was working on one and it would run decent for awhile then run terrible, and they worked on it alot, and when they replaced the computer, it fixed it. So I just adding that info here since these websites are for looking up problems/fixes. |
Re: Do ECU's ever go bad in these cars? now that you updated post #3 , you have still not stated if you have any codes. that symptoms sounds like the maf. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by tunedperformanc
(Post 5212070)
now that you updated post #3 , you have still not stated if you have any codes. that symptoms sounds like the maf. |
Re: Do ECU's ever go bad in these cars? If your not even getting a code 12 the ecm is junk |
Re: Do ECU's ever go bad in these cars?
Originally Posted by tunedperformanc
(Post 5212090)
If your not even getting a code 12 the ecm is junk |
Re: Do ECU's ever go bad in these cars? a ecm is fairly cheap, other than that You might want to ohm your injectors while the engine is hot and check your fuel pressure. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by tunedperformanc
(Post 5212118)
a ecm is fairly cheap, other than that You might want to ohm your injectors while the engine is hot and check your fuel pressure. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 89GTASC
(Post 5211433)
Could be. we dont know what problem is. not cranking well i meant sometimes it cranks sometimes it doesn't. car always had issue that once it runs for awhile if you kill it you have to wait 5 minutes before it'll crank back up. car started acting up about 1.5 yr ago, it used to run well for 30 minutes, then act retarded like its missing hesitating, rough idles etc. let the car sit for 1-2 days, then it would run good again for 1st 30 minutes. it did this for months.... but now 1.5 yr later, we are trying to figure out what the problem is putting new parts like distributor w control module, plugs, wires, cap , rotor, fuel filter.... car did a lot of sitting, so don't know. we think maybe the computer, some thing called electronic spark control module, i thought maybe coolant temp sensor or air intake sensor since car never drove well under 60 degrees. but what you said faulty injectors, it very well could be... maybe i should try doing something about the injectors. More info: we can crank it by spraying quick start spray into the throttle body, and it will bust off, but still it runs poorly. so fuel injectors work, but yeah you could be right, maybe they could be faulty. When i say run poorly, its the old symptom when it used to run good for 1st thirty minutes, then starts to act retarted. I remember when i hit a bump in the road 1 time it started acted retarded, then i hit another bump and it went back to running well again. so that sorta doesnt sound like injectors to me, but like a loose wire or something.. BTW, to save confusion, when I hear "crank" I think of the engine being turned by the starter. What I think you mean to say is the engine cranks but won't start. Specifying this may help others understand what you mean to say. I just picked up on a small clue. Have you used a scan tool to view coolant temp on ECM data? You may have a bad coolant temp sensor or circuit. More likely though, it's injectors. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by ASE doc
(Post 5213256)
"Starts and runs for a few minutes, starts to run badly, then dies and won't restart until it cools down." What you're describing sounds alot like a faulty ignition control module or injectors. Nothing like any ECM failure I've ever seen. "It starts with starter fluid" really sounds like injectors. BTW, to save confusion, when I hear "crank" I think of the engine being turned by the starter. What I think you mean to say is the engine cranks but won't start. Specifying this may help others understand what you mean to say. I just picked up on a small clue. Have you used a scan tool to view coolant temp on ECM data? You may have a bad coolant temp sensor or circuit. More likely though, it's injectors. And thanks, yeah crank vs start. To me they mean the same, but I can see the difference now... btw another lady at my autozone has a 91 firebird 350, and she says her car does the same thing, when outside is cold <60 degrees, her car doesnt run well either. (But this is an "old" symptom, a symptom I lived with even when the car was running "good" to me.), but you never know it could be related. This and the other "old" symptom of car not being able to restart quickly after engine shut down, that symptom has been there since car had 150k miles, and car now has 208k miles. And it's not always like that. Like the other day the engine died and it restarted ok.(still run's terrible though). The 4 parts we were looking at was 1 week ago was: ignition control module, ignition spark control module(yeah 2 different ones), coolant temp sensor, and intake air temp sensor. But we replaced the distributor which has the ignition control module included in it. We even thought to do it again thinking maybe the distributor we put in was faulty. but i think they tested it before we put it in, so chances should be 99% that the distributor/ignition control module are good. And we leaned away from coolant temp sensor and other temp sensor; because they "should" give a trouble code light if they went bad. So we picked up an ECU & ignition spark control module yesterday, but we wont be able to try it until his next visit which will probably be in 10 days from now. I'm going to tell my dad all the info you already given me; especially how to test the fuel injectors more. He tested it some already using ohm/volt meter and advice we got from another guy. And per the result of that test, both the guy and my dad feel there is a grounding issue coming from somewhere and its more than likely the ECU. But we didn't test it like what you said previously to do. I believe he tested one side of the injector plug and got 12 volts, and the other side and got 12 volts, and it sounded like that is not suppose to happen. he did while engine dead, and then key turn on, and i want to say while running but not positive. And they way they spoke about it, I guess both sides aren't suppose to have 12 volts. So we now are considering it could be injectors also; especially from info and what you are saying. (Damn see what I mean, I write books also). Thanks for your knowledge man. It is a puzzle. |
Re: Do ECU's ever go bad in these cars? While the car is running drop the ecm down and put your hands on it. They are multi-layer boards and by squeezing lightly on the ecm you may be able to munipulate it to get the engine to run correctly. Check your engine grounds and make sure the are clean, tight, no frays. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 85whtz28
(Post 5214154)
While the car is running drop the ecm down and put your hands on it. They are multi-layer boards and by squeezing lightly on the ecm you may be able to munipulate it to get the engine to run correctly. Check your engine grounds and make sure the are clean, tight, no frays. |
Re: Do ECU's ever go bad in these cars? Both side of the injector will have 12 volts with key on, engine off. With engine running, one side should pulse between 0 volts and 50 volts( 50 volts is the injector's inductive snap as the magnetic lines of force are released when the circuit opens). A shorted or open injector will just flash between 0 and 12 volts because it doesn't develop magnetic force. Tap testing is a popular method for testing any module. By gently squeazing and tapping the module we can cause a loose connection or damaged printed circuit board to reveal itself. Still think your problem is more likely injectors. Obviously you've verified that the dist is okay. As far as the coolant temp sensor goes, it can fail "in range", meaning that it will give a false reading to the ECM without causing a code to set. These old ECMs aren't smart enough to know they're being lied to. Unless the ECT goes open or short, the ECM will never know it's not okay. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by ASE doc
(Post 5214509)
Both side of the injector will have 12 volts with key on, engine off. With engine running, one side should pulse between 0 volts and 50 volts( 50 volts is the injector's inductive snap as the magnetic lines of force are released when the circuit opens). A shorted or open injector will just flash between 0 and 12 volts because it doesn't develop magnetic force. Tap testing is a popular method for testing any module. By gently squeazing and tapping the module we can cause a loose connection or damaged printed circuit board to reveal itself. Still think your problem is more likely injectors. Obviously you've verified that the dist is okay. As far as the coolant temp sensor goes, it can fail "in range", meaning that it will give a false reading to the ECM without causing a code to set. These old ECMs aren't smart enough to know they're being lied to. Unless the ECT goes open or short, the ECM will never know it's not okay. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 85whtz28
(Post 5214154)
While the car is running drop the ecm down and put your hands on it. They are multi-layer boards and by squeezing lightly on the ecm you may be able to munipulate it to get the engine to run correctly. Check your engine grounds and make sure the are clean, tight, no frays. |
Re: Do ECU's ever go bad in these cars? Right, there is only one circuit board but the circuit board has multiple layers of glass-epoxy or like material making it multi-layer. |
Re: Do ECU's ever go bad in these cars? Well smashing the ECM will not affect anything. On the bottom of the ECM there are 2 square corks which are used to absorb shock. On the upper section of the ECM, there is metal bracket that goes from side to side which is used as a support/screw mount. So no matter how hard you smash, it won't do no good. Best thing to do is shake it vigorously. But then agian, what if the ECM ain't the problem and due to the smashing and shaking, you cause a solder pin or joint to break? Then you jus created a problem that is very tough to find. |
Re: Do ECU's ever go bad in these cars? To quote a line from Jurasic Park II, "technology and violence are not good bed fellows". These automotive electronic components are engineered to withstand a fair amount of jostling. But banging on, hard squeezing, or vigorously shaking them could ruin an otherwise good module. One thing that I should also mention is the risk of damage from ESD, or "electrostatic discharge". The OEMs have printed reams of paper warning us not to disassemble any electronic module without taking precautions to guard against ESD. I have not had an issue myself but I have heard of problems. Just the static electricity in the touch of a finger can destroy an integrated circuit. The recommended procedure for preventing ESD is to work on a grounded metal work surface and attach a grounding strap to your wrist before opening the unit. Danger of damaging an ECU is also why we want to avoid partial connection to power. In otherwords, never connect or disconnect an ECU to a live circuit. Be sure that the Batt- is disconnected and, if the car has an airbag, that you've given the caps in the inflatable restraint module a few minutes to discharge before disconnecting or reconnecting the ECM. |
Re: Do ECU's ever go bad in these cars? Yup. When opening a ECM, there is the risk of the circuitboard having more or less charge than the body. When this occurs, upon contact of two different objects with different charges, a spark occurs. All it takes is a few volts to program a chip. A spark has more than 10,000 volts. Imagine that kind of voltage flowing through a chip. Total disaster. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by ASE doc
(Post 5214509)
Both side of the injector will have 12 volts with key on, engine off. With engine running, one side should pulse between 0 volts and 50 volts( 50 volts is the injector's inductive snap as the magnetic lines of force are released when the circuit opens). A shorted or open injector will just flash between 0 and 12 volts because it doesn't develop magnetic force. Tap testing is a popular method for testing any module. By gently squeazing and tapping the module we can cause a loose connection or damaged printed circuit board to reveal itself. Still think your problem is more likely injectors. Obviously you've verified that the dist is okay. As far as the coolant temp sensor goes, it can fail "in range", meaning that it will give a false reading to the ECM without causing a code to set. These old ECMs aren't smart enough to know they're being lied to. Unless the ECT goes open or short, the ECM will never know it's not okay. but what do I do if it IS the fuel injectors? Do I need to buy new ones? Where is best place to buy fuel injectors? I just looked at autozone and looks like $365 for a set of 8 replacement in injectors, Kind of pricy.. I think were gonna try to coolant temp 1st... then go from there.. and I did relay the fuel injector testing info you gave.. thanks. |
Re: Do ECU's ever go bad in these cars? 2 things. check you alternator and battery i know sounds dumb but mine started running bad threw lots of money at it finely took it to the dealer and they found a bad alternator. runs great now. seconed i read that the ecm runs closed loop when under 160 degrees and open loop when at or above 160 degrees. so when its cold it runs of the default program and when it warm up it starts using the data from the sensors.at least thats the way i understand it works. if i am wrong please forgive me |
Re: Do ECU's ever go bad in these cars?
Originally Posted by kustomiser
(Post 5224360)
2 things. check you alternator and battery i know sounds dumb but mine started running bad threw lots of money at it finely took it to the dealer and they found a bad alternator. runs great now. seconed i read that the ecm runs closed loop when under 160 degrees and open loop when at or above 160 degrees. so when its cold it runs of the default program and when it warm up it starts using the data from the sensors.at least thats the way i understand it works. if i am wrong please forgive me |
Re: Do ECU's ever go bad in these cars? A set of Bosch III'S from our very own vendor SouthBay. For 8, it's less than $170. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5224835)
A set of Bosch III'S from our very own vendor SouthBay. For 8, it's less than $170. Do you happen to know how many lb injectors our 5.7TPI uses? And what is the lb rating for those Bosch 3's you mentioned? But good to know $170 much better than $365. Umm. Small update.... We installed the coolant temp sensor. That was not it. We then tried some thing called a 'ignition spark control module' (This is not ignition control module), it's something else... and we don't believe it did anything... We are the middle of installed the new ECU, but read an instruction warning saying that we should test ALL SOLONOIDS before installing, becuase a faulty solonoid can cause the ECU to go bad. My father is equating SOLONOID to the fuel injectors saying each fuel injector has a solonoid(YEah I don't really know what solonoid is, but I guess there is 1 for each fuel injector). We did see something we did not like on our original ECU,,, there was some insulation material designed to keep water from entering the ECU box looks like it was not installed properly as 1 side had like a "gash" in it, so it may have been possible for water to enter.. So tommorrow we test the solonoids on the fuel injectors(let me know if there are other solonoids we are suppose to check)... then I guess we will see if the new ECU fixes it... if that doesn't do it,, then yeah I guess the next thing will be fuel injectors. Thanks for all the help. |
Re: Do ECU's ever go bad in these cars? 305 uses 19 lb injectors while the 350 uses 21 lb injectors. As for the solenoids, there a few of them. I'm not too sure if the fuel injectors are one of them. So from what I can remember from the top of my head is the EGR Solenoid, Evap Canister Solenoid, and uuuummmm. I'll look them up in my GM Camaro Shop Manual when I get home. I'm currently at the in laws having dinner. |
Re: Do ECU's ever go bad in these cars? My 86 z28 was acting that way and it wound up being a faulty fuel Pump and the pressure was good but I had a bad fuel pump that caused my problem!!!! |
Re: Do ECU's ever go bad in these cars?
Originally Posted by ahankins32984
(Post 5225485)
My 86 z28 was acting that way and it wound up being a faulty fuel Pump and the pressure was good but I had a bad fuel pump that caused my problem!!!! At 1st when we started it, it busted off real good and we was hopeful, but after a few minutes of idling you can hear it still not running well.... Question: The guy at autozone said our fuel pressure should by 60 pounds, but the book says it should be between 34-47 pounds... And when we checked ours it was 40 pounds.... so we thought we were good... Per you... the fuel pump might still be my problem? Does anybody know how many pounds it should be?? Ok I'll ask my other question to ASE DOC... |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5225305)
305 uses 19 lb injectors while the 350 uses 21 lb injectors. As for the solenoids, there a few of them. I'm not too sure if the fuel injectors are one of them. So from what I can remember from the top of my head is the EGR Solenoid, Evap Canister Solenoid, and uuuummmm. I'll look them up in my GM Camaro Shop Manual when I get home. I'm currently at the in laws having dinner. |
Re: Do ECU's ever go bad in these cars? Lots of good info on this will be using it on my own 89 GTA. |
Re: Do ECU's ever go bad in these cars? 2 Attachment(s) Hi, can someone identify the ecm attachments so i know what to get for a replacement as there is no sticker on the case. It is out of an 85 2.8 mpfi camaro automatic any help would be greatly appreciated Gary |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 89GTASC
(Post 5226288)
Hey when you got your Bosch3 injectors, did they come in a kit? WOuld the kit include any gaskets etc...? Becuase we might just replace our injectors as it could be one of our problems... |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 89GTASC
(Post 5226286)
Ok.. we replaced the computer and problem still persists... At 1st when we started it, it busted off real good and we was hopeful, but after a few minutes of idling you can hear it still not running well.... Question: The guy at autozone said our fuel pressure should by 60 pounds, but the book says it should be between 34-47 pounds... And when we checked ours it was 40 pounds.... so we thought we were good... Per you... the fuel pump might still be my problem? Does anybody know how many pounds it should be?? Ok I'll ask my other question to ASE DOC... |
Re: Do ECU's ever go bad in these cars?
Originally Posted by garyo
(Post 5226348)
Hi, can someone identify the ecm attachments so i know what to get for a replacement as there is no sticker on the case. It is out of an 85 2.8 mpfi camaro automatic any help would be greatly appreciated Gary this was used in 85 only on 2.8L and 305 tpi in the f-body and l98 in the Y |
Re: Do ECU's ever go bad in these cars? Thank you,also i cant seem to find the burn off module as i thought it was also under dash and next to the ecm. Many thanks for the reply Gary |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5226426)
the AZ guy is smoking crack. Normal pressure is 50 lbs when the key is turned. While running, the fuel pressure should be around 45-50 lb. You CAN run the pressure at 60 lbs but you run the risk of damaging the tiny needle that retracts when the injectors opens (according to my TPI Swappers Guide Book). |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5226418)
Yup. They came as a set of 8 and they have the o rings installed. All you gotta do is lube the ring with motor oil and follow the instructions. The little lock rings are not to be used because there is no slot on the injector for the lock ring to grip. That's all that comes with injectors, just the o rings. Man I think I'm bummed out today.. What is best way to contact that vendor that sells bosch3's for $170 kit? I'm guessing they have a website.. |
Re: Do ECU's ever go bad in these cars? So my dad wanted me to post the question and ask if anybody knows if there is a good performance shops that have diagnosing tools to debug (our) cars? I am kinda of the opinion that me being able to find a car performance shop that would be able to troubleshoot my car better than we can is going to be difficult to find. Does anybody know if there are good places to take our cars for troubleshooting? Do places like that still exist for our cars? |
Re: Do ECU's ever go bad in these cars? |
Re: Do ECU's ever go bad in these cars? Goodmorning TunedPerformance. Ummm. The best thing to do is buy everything new. Buy new sensors. But mainly, a new wiring harness from Painless (they sell new wiring harnesses). But not all sensors are available. Also replacing relays may help too. Or you can go to a mechanics shop that has a Snap on diagnostics tool that connects to the ALDL port which will display real time data. The goal is to find any readings that don't look normal. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5226978)
Goodmorning TunedPerformance. Ummm. The best thing to do is buy everything new. Buy new sensors. But mainly, a new wiring harness from Painless (they sell new wiring harnesses). But not all sensors are available. Also replacing relays may help too. Or you can go to a mechanics shop that has a Snap on diagnostics tool that connects to the ALDL port which will display real time data. The goal is to find any readings that don't look normal. We tried the computer, that didn't fix it. So I think next we will try the fuel injectors. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by 89GTASC
(Post 5227147)
Thanks for this info & info you gave about the Bosch3 injectors; I ordered my set today. With the 10% TGO discount; it was listed at 165.99 on the site with 5.50 shipping it came to 154.90 shipped. Much better than a set I saw on autozone.com saying $365.00 for 8. We tried the computer, that didn't fix it. So I think next we will try the fuel injectors. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5227207)
no problem man. let us know your results with the fuel injectors.:thumbsup: ASE DOC seemed to think it was injectors, and it does make sense that it could be that, so that will be our next try. |
Re: Do ECU's ever go bad in these cars?
Originally Posted by Chevy86 IROC-Z
(Post 5227207)
no problem man. let us know your results with the fuel injectors.:thumbsup: |
Re: Do ECU's ever go bad in these cars? It took me only about 45 minutes. But I already knew the process. Jus remember that when you remove the runners, there are 2 hidden bolts that unscrew from under the plenum. But for both of you, I'd say about 2 hours. |
Re: Do ECU's ever go bad in these cars? Also, I found a diagram inside my GM Camaro shop manual. It has all the relays and sensors, and solenoids. I'll upload it in a bit so that you can check the resistance/ohms to prevent burnin out the ECM. |
Re: Do ECU's ever go bad in these cars? 1 Attachment(s)
Originally Posted by 89GTASC
(Post 5225296)
Cool. Bosch 3's huh? IS that a good recommended size for our Engines? Do you happen to know how many lb injectors our 5.7TPI uses? And what is the lb rating for those Bosch 3's you mentioned? But good to know $170 much better than $365. Umm. Small update.... We installed the coolant temp sensor. That was not it. We then tried some thing called a 'ignition spark control module' (This is not ignition control module), it's something else... and we don't believe it did anything... We are the middle of installed the new ECU, but read an instruction warning saying that we should test ALL SOLONOIDS before installing, becuase a faulty solonoid can cause the ECU to go bad. My father is equating SOLONOID to the fuel injectors saying each fuel injector has a solonoid(YEah I don't really know what solonoid is, but I guess there is 1 for each fuel injector). We did see something we did not like on our original ECU,,, there was some insulation material designed to keep water from entering the ECU box looks like it was not installed properly as 1 side had like a "gash" in it, so it may have been possible for water to enter.. So tommorrow we test the solonoids on the fuel injectors(let me know if there are other solonoids we are suppose to check)... then I guess we will see if the new ECU fixes it... if that doesn't do it,, then yeah I guess the next thing will be fuel injectors. Thanks for all the help. Attachment 372571 |
Re: Do ECU's ever go bad in these cars? So you should have 4 solenoids to test with a multi-meter and 4 relays to test as well. SOLENOIDS TO TEST AIR port (switch) solenoid AIR Converter (diverter) solenoid EGR solenoid Fuel Vapor Canister Solenoid RELAYS TO TEST Fuel pump relay Primary fan relay Mass Air Flow Sensor Relay Mas Air Flow Sensor Burn-off Relay :) |
Re: Do ECU's ever go bad in these cars? well we are starting the fuel injector work today. we watched some youtube vids last night and there were some showing how to do it. even one for our engine. took person in vid 2.5 hrs. We are curious if we will need to buy new plenum gaskets or not. we will see.. [JAA:Looks like we can re-use] Did you install the fuel injectors with the adapters? [JAA:Nevermind, injectors went in ok with adapters]. We probably will not finish putting things back until tommorrow.. |
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