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Discussion Starter · #1 ·
Hey guys, a couple of weeks ago I posted where my gn started running really bad and the scanmaster showed ------- and later a code 42. There was a vac. hose sprung a bad leak, I fixed it and at first it didn't run much better but after a couple of days and resetting the ecm 2 times it ran ok with no codes. Since then I've only driven it a couple of times but it ran normal. Well!! today I drove it to town, about 5 miles, it ran great there and I had to go to about 2 different places and it still ran great. I made a stop at the dollar store and when I came out and started it , it ran crappy again. It would hardly idle and did die on me once, the scan master was showing zero's on almost everything. IAC's TPS,CC was doing nothing. The check engine light was flashing off and on steadly. I started home and barely made it, the farther I went the worse it ran. When I did get home it barely made it into the driveway. What do you guys think?? I have never checked/fixed the grounds on the head, do you think that would do it?? Oh yeah! the battery voltage on the sm was showing 0 also. Seems like the ecm was not getting power. About 5 hours later I started the car and all seemed well again. I didn't drive it but it idled good and sm seemed ok. What do you think.
 

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clean the prongs on the chip with an eraser, make sure none are bent out of shape, and reinstall.
 

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Steve is probably right about cleaning the pins but a FYI about the Scanmasters lack of info..

No info denotes your ECM is in backup mode (limp home mode. Sometimes you can restart the car and things wil run normal though. Happened to me on a car cruise. I participated in a little exhibition of speed and the car died after coming off the throttle abruptly. Had to restart the car on the roll and once up to 50 mph or so it began cutting out. Continued driving and & it would run OK at lower speed but had trouble keeping up with the cars in front of me.

I began looking at the gages & saw EGT temp going to 1300+ & the fuel pressure rising & falling. Finally I checked the scanmaster & it was not getting any info at all & that clued me in that the car was in backup mode.

Only out of the ordinary thing I'd done was the rolling restart so I turned off the key, restarted the engine and it was all back to normal once again. My best guess is the cam sensor had a hiccup on the 1st restart & that caused the ECM to go to backup.
 

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Discussion Starter · #4 ·
Thanks for the responses! Steve I will try cleaning the chip, it hasn't been in there long though. The fact that it has done it before makes me think that it will do it again.What do you guys think about the grounds on the PS head, would they cause it ?? I'm going to do what you sugested and check the connections at the ECM and clean the/relocate the grounds this weekend. I'll let you know. Thanks again for your input.
 

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Remove and clean all grounds on back of block. This may not your problem but I would clean it anyway. Check battery connections and ground to block and pos to starter. Make sure ECM orange wire at battery is not grounding out. recheck the ecm as Steve said. It may look OK but one of the legs may be off just a hair. Also unplug the ecm and look at the contacts some times they get corroded. Clean with Radio Shack contact cleaner. It comes with a brush attachment. Then make sure none of the pins backed out of the ecm harness when you put the ecm back on. Electrial problems are always fun crazy
 

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When the check engine lite flashes like that, it is in limp home mode and is usually a code 51 which is usually a badly seated chip, but can be a bad chip, or an ecm problem.

If you go to my site and click on troubleshooting then trouble codes and go to 51, you will see the factory run down.

Not good to drive it that way if the car has larger injectors as the limp home mode is calbrated for small injectors and you can wash the cylinders down in a hurry if it is run in that mode.
 

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Discussion Starter · #7 ·
Thanks for the replies!! I got under it yesterday and looked at the grounds, just like I've seen people on the board talking about them-- what a pita! Looks like I need to drop the starter to free up the wire bundle the grounds come out of in order that I will have room to work on them. Does that make sense? While I was under there I looked at the crank sensor, it was very oily, will that affect it you think? Anyway I plan on working on it during the next few days. I have a guy helping me install gutters also. I have to work things in. And you guys thought Steve Wood was the only rock farmer??
 

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I am a goat herder also, these days. :)
 

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Discussion Starter · #9 ·
Well, I finally got those da-- grounds off!!! I knew they would be a PITA but dang! I am going to relocate to another spot on the block. I'm bolting all of them together to a "battery cable sized" wire that has factory brass ends and if it is long enough attach with the bat. ground, if not somewhere to the block. I will then do the other things you guys suggested. I will keep tou informed. OH Yeah! Steve, are you still on the Dr, Pepper?
 

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Yeah...the only drink for real men! They don't sell it in West Virginia, tho!

You can attach those grounds on the engine top, or in a terminal box on the firewall with a ground strap to the engine ala John Spina.
 

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Discussion Starter · #11 ·
Sorry it took so long - still busy herding rocks--er--anyway, I finished grounding the old head bolt,attached them as described to a bat cabe sized wire and wound up that it reached to the other side of the motor. I neatly routed it to the bolt on the alt. do you think this will do ok? I then took out the ecm inspected the harness plugs to insure they were install good in the first place ( they appeared ok) cleaned the chip and also the calpack one while I was there. Inspected the ecm pins and reinstalled. I drove it to town and it made the trip witout going into limp mode. Here is the difference tho. Ran strong but at about 2/3 throttle it jingled pretty loud but didn't show anything on the SM. was cutting out also. I tried it again on the return trip and it would cut out the same but I didn't hear the jingle. I was just wondering if when I drove it home the last time it was run ( it was in limp) if it could have fouled the plugs and perhaps if I drive it some more it might clear its self? Still don't know if the original problem is fixed. here are sm readings taken when I got back home today. 02-370's to 600's
AF--02
LB--23-24
bat--13.2-13.5
int--125--132
bl--134
clt--165
ats--97--seems funny,car was in garage but it was only about 85 in there
r--825-900
tps--.46
iac--19
cc-- counting upwards at a good rate
mal--00
fuel pressure--38 line on
What do you think?? schizo
 
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