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Car runs but runs poorly after crank position sensor and icm update


Danpatters583

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Hello all,

 

I have 1990 Reatta. I picked it up a few weeks ago. It was running rough when I got it. Found it was a fuel filter filled with rust. So needless to say the entire fuel system minus injectors got replaced. After doing so car ran great. I decided to replace the crank position sensor and update to the Delco ignition system. I put it all back together and now runs rough. It starts but takes a minute or so and then hesitates and runs rough. I've swapped back to the original Magnavox set up and crank position sensor and still same results. I'm a bit lost honestly. Is it possible I fried the ecu some how? Any help would be appreciated. 

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No I have not. I do not have an engine light on. So I figured there would not be Any thing to read. Unless I am mistaken?

 

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You will likely need to do some basic troubleshooting, much of which can be done through the onboard diagnostics. The ECM is smart and stupid at the same time. It doesn't know if it is receiving bad information unless it is far out of range or missing altogether. Start by going through diagnostics and see if there are stored or pending codes. Read the various sensors in real time by scrolling through them while the engine is running, throttle position, MAF reading, engine and intake air temperature etc.. Since the ignition modules have been changed back and forth, check the plug on the ICM for bent or pushed back pins, possible double gaskets on the plug and make sure it is clean and tight. Push on the plug ends when installing rather than relying on the bolt to pull it in. Check the plug wires for correct routing and integrity, the two different styles have somewhat different connection patterns.

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Is checking the codes on this car like any other GM obd1 were you jumper pins one and three and it flashes the engine light? Also, is there a way on a 1990 to watch the sensors in real time with out a computer hooked up to the diagnostics port? I'm not super familiar with the Reatta's this is my first one. 

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8 minutes ago, Danpatters583 said:

Is checking the codes on this car like any other GM obd1 were you jumper pins one and three and it flashes the engine light?

No. The Reatta has much more information. It is better that any ODB1 scanner I've seen. Click "Diagnostics" in the menu at the top of the page. In the dropdown menu you will find how to check the codes on your Reatta. All the code charts are there and be sure to go over the Diagnostics booklet. It is your best friend when troubleshooting your Reatta. Let us know what codes you find. If you have questions feel free to ask.

 

 

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Ronnie is right about the tutorials on this site, they are invaluable. I made the mistake of assuming you are familiar with the built in scanner and diagnostic system.  It takes a bit of practice but once you get the hang of it, you can get into it on the fly; eyes on the road of course?

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Thank you both. Sorry for the delayed reply. I must admit this car is quite impressive lol. I attemtped to access it and I think I got some codes but im not sure if they are the ones I'm looking for.

 

My codes are as follows

 

6410H

6420H

6552H

R061H

 

Again thank you guys for the help. I do appreciate it!

 

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Also if it helps here is a list of all the things ive replaced before the issue started.

 

Fuel tank, fuel pump, fuel filter, spark plugs, wires, belt, hoses, air filter, alternator, battery, belt tensioner, and at filter/fluid.

 

Car ran great minus one time it stalled while pulling into my driveway. After that, i was trying to be preventative and replaced the crank position sensor and updated to the Delco ignition set up as previously stated. Hope this may help generate ideas. 

 

 

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1 hour ago, Danpatters583 said:

My codes are as follows

 

6410H

6420H

6552H

R061H

The first digit "6" in the codes you list is probably a "b" that indicates they are BCM codes. BCM codes won't effect how the car runs so I don't think they are causing your problem.  However, the code b410H indicates a charging problem so make sure the gauges show the battery is being charged when the engine is running and shows at least 12 volts. Low battery voltage might cause the engine to run rough.

 

The code b552H indicates the battery has been disconnected and normally that isn't a problem. But sometimes after the battery has been disconnect for a period of time the ECM has to go through a relearn process. Sometimes during that relearn process the engine will run rough but it shouldn't take long for it to smooth out and start running normally. The next time you start the engine, bring it up to about 2000 RPM and hold it there for a couple of minutes or so and see if it starts running correctly.

 

I'm not familiar with the code R061 ("H" indicates history). Maybe it is unique to a 1990 model and isn't listed in my service manual.

 

On 11/25/2020 at 10:07 PM, Danpatters583 said:

I decided to replace the crank position sensor and update to the Delco ignition system. I put it all back together and now runs rough. It starts but takes a minute or so and then hesitates and runs rough. I've swapped back to the original Magnavox set up and crank position sensor and still same results. I'm a bit lost honestly. Is it possible I fried the ecu some how?

I doubt you have damaged the ECU unless you shorted out the wiring somehow. They are very reliable and don't go bad too often.

 

I think 2seater gave you excellent advice when he recommended checking the connections to the ICM and the crankshaft position sensor and checking for bent pins in the connector.

 

When you changed the sensor the second time did you see any indication that the one you replaced had been damaged by the metal rings on the harmonic balancer touching it?

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I don't have my manual handy but I think the 061 code is for the air bag and I suspect it relates to battery power disconnect too. I know I have seen it on mine.

 

Please forgive me if I am off base, but you did replace the crank sensor, right? Sometimes that gets confused with the cam sensor which is in the front cover. The crank sensor is behind the damper on the crankshaft which must be removed for access. 

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2 hours ago, 2seater said:

I don't have my manual handy but I think the 061 code is for the air bag and I suspect it relates to battery power disconnect too. I know I have seen it on mine.

 

Please forgive me if I am off base, but you did replace the crank sensor, right? Sometimes that gets confused with the cam sensor which is in the front cover. The crank sensor is behind the damper on the crankshaft which must be removed for access. 

Yes I did replace it. Ive removed the balancer a few times already lol. 

 

4 hours ago, Ronnie said:

The first digit "6" in the codes you list is probably a "b" that indicates they are BCM codes. BCM codes won't effect how the car runs so I don't think they are causing your problem.  However, the code b410H indicates a charging problem so make sure the gauges show the battery is being charged when the engine is running and shows at least 12 volts. Low battery voltage might cause the engine to run rough.

 

The code b552H indicates the battery has been disconnected and normally that isn't a problem. But sometimes after the battery has been disconnect for a period of time the ECM has to go through a relearn process. Sometimes during that relearn process the engine will run rough but it shouldn't take long for it to smooth out and start running normally. The next time you start the engine, bring it up to about 2000 RPM and hold it there for a couple of minutes or so and see if it starts running correctly.

 

I'm not familiar with the code R061 ("H" indicates history). Maybe it is unique to a 1990 model and isn't listed in my service manual.

 

I doubt you have damaged the ECU unless you shorted out the wiring somehow. They are very reliable and don't go bad too often.

 

I think 2seater gave you excellent advice when he recommended checking the connections to the ICM and the crankshaft position sensor and checking for bent pins in the connector.

 

When you changed the sensor the second time did you see any indication that the one you replaced had been damaged by the metal rings on the harmonic balancer touching it?

The 6 being a b makes alot more sense. The low battery voltage amd battery disconnected codes make sense. I did have it disconnected for a few days. The low voltage it probably due to the fact I dont have the belt hooked back up. I have it running on the start/charge option on my battery tester and it doesnt seem to drop below 13v while running. 

 

I did accidentally have the sensor too close the first time and it did graze a few teeth of the wheel. Part of the reason I replaced it again. Didnt know if that was super critical or not so I decided to error on the side of caution. I do think 2seater is right. The connection to the icm was a bit tight and i dont remember if I used the bolt to sink it down or not. So im gonna try that again today. Ill let you know what happens

 

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9 minutes ago, Danpatters583 said:

I have it running on the start/charge option on my battery tester and it doesnt seem to drop below 13v while running. 

That might be your problem. Most battery chargers don't supply pure DC voltage. The AC ripple in the power coming from them can run the computers crazy. I did that one day. I had a dead battery and I boosted it with my charger and forgot to unhook the charger. The engine started and stayed running but my CRT was strobing and the engine wasn't running good. I unhooked the charger and all was good.

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I didnt think about that actually good point. I did just clean some grounds and reseated the icm connector and checked for broken or damaged pins. Every thing looks fine. I will put the belt back on and give her a whirl. See what happens and let you know. 

 

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So I put the belt back on and same results. Running at 14.5 volts. I did while it was running play with the diagnostics thing some more. My tps appears to be working. In idle its at .4 volts when I turned it off and floored it it showed 4.23 volts. So im assuming its good. So I turned it back on and cycled through until i saw the the knock sensor readouts and no matter what amount of throttle I give it still shows 0 degrees. Shouldn't it be trying to retard the timing a little bit considering its misfiring and running rough?

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No, it should not be looking to retard timing unless you get into prolonged knock situations. Rpm itself has no effect. There are two knock related readings, one is the cumulative knock counts while will increase from time to time, just from the noise generated from starting the engine. The other is called spark angle for some reason, and that is the actual amount of spark retard commanded in response to the knocking itself. Don't be alarmed if the knock counts have increased but there would be a concern if that number is increasing during normal driving. 

 

The TPS reading sounds to be in normal range and you can check in a little more detail with the key on and engine off just to see if it increases smoothly as the throttle is increased and doesn't jump all over. I doubt this is a problem here. Observe the MAF reading. it should be relatively steady at any constant throttle opening and increase instantly as the throttle is opened. One major culprit in poor running can be the MAF sensor even if it appears to be working. Simply disconnect it and start the engine. If the idle improves, the MAF sensor is likely bad. You can also tap on the black casing while it is running to see if it affects the idle. Do not be surprised if the engine stumbles or quits if you connect or disconnect the MAF with the engine running. It will do no harm but you will probably find a code for it later. Lastly, observe the O2 sensor voltage and cross counts with the engine at an elevated idle, say 1500-2000 rpm for a minute or so. The O2 reading should be cycling high to low constantly and the more cross counts indicated, the better.

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On 11/25/2020 at 10:07 PM, Danpatters583 said:

I decided to replace the crank position sensor and update to the Delco ignition system. I put it all back together and now runs rough.

 

59 minutes ago, Danpatters583 said:

...its misfiring and running rough?

Is is possible you got the spark plug wires crossed? Might be worth checking...

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I mentioned the plug wires earlier for the same reasons. It has caught many of us out, me included, and the connection pairings should be the same but the configuration of the two styles of coils is very different. Maybe a wild guess, but when we were working on the red car for the grandson, we inadvertently failed to get a good connection on one injector, #1 cylinder after injector inspection and spark plug wire rerouting and insulating. The plug for the injector was laying in place but was not firmly snapped on. Had an intermittent miss and slight hesitation.

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5 hours ago, 2seater said:
5 hours ago, Ronnie said:

 

Is is possible you got the spark plug wires crossed? Might be worth checking...

The TPS reading sounds to be in normal range and you can check in a little more detail with the key on and engine off just to see if it increases smoothly as the throttle is increased and doesn't jump all over. I doubt this is a problem here. Observe the MAF reading. it should be relatively steady at any constant throttle opening and increase instantly as the throttle is opened. One major culprit in poor running can be the MAF sensor even if it appears to be working. Simply disconnect it and start the engine. If the idle improves, the MAF sensor is likely bad. You can also tap on the black casing while it is running to see if it affects the idle. Do not be surprised if the engine stumbles or quits if you connect or disconnect the MAF with the engine running. It will do no harm but you will probably find a code for it later. Lastly, observe the O2 sensor voltage and cross counts with the engine at an elevated idle, say 1500-2000 rpm for a minute or so. The O2 reading should be cycling high to low constantly and the more cross counts indicated, the better.

I removed the maf connector while it was running like suggested and it stalled immediately. Plugged it back in same problems. I checked the cross counts and in idle it was about 25. At 2k rpm about 38. Voltage didn't really change much. Flucuated from .1 up to about .7. 

 

It is possible my wires are not making a good connection. I replaced the wires with the old magnavox system still on. Should I buy the wire set for like a 91 reatta instead? Are the connections that much different between Delco and Magnavox? 

 

Ronnie: it's entirely possible. Ive checked it three times but the best wiring diagram/firing order diagram I got is from a 95 Riviera which I assumed had the same firing order and wire locations on the coil packs. If i recall correctly 6-3 are on the top coil,2-5 are on the middle coil, and 1-4 are on the bottom coil. With even number cylinders on the top of each coil.

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