[Bertscova]

This morning i when out to move the van to install the transgo servo's that I ordered and it started and ran a little rough ran for a total of about 30 sec then just shut off like i turned the key of ( no stumble or anything ) just shut off and now it will not start doesn't even sound like it is firing. I've replaced the fuel pump last week because of low fuel pressure. The The ECM is from a Junk yard. The orig ECM was a #4482 so I replaced it with a #7747 ECM. I have noticed that the last couple of starts it would run rough until it warmed up then ran fine. Another intermittent problem is an idle issue, sometimes when in gear it will idle down to an almost stall then recover. It will do that when in neutral as well but not as extreme as when in gear. I'm thinking Its an ecm issue. The ECM looked old like it had been on the shelf for awhile had some rust stains on cover. I got it anyway because i needed it for a core and decided to try it out first before buying a reman ecm. The ecm prom is new from http://www.tbichips.com .I haven't checked to see if there is spark but will do that now. Will post results of the spark check. If anyone has any other ideas please chim in. :banghead:

 

[astro355]

This morning i when out to move the van to install the transgo servo's that I ordered and it started and ran a little rough ran for a total of about 30 sec then just shut off like i turned the key of ( no stumble or anything ) just shut off and now it will not start doesn't even sound like it is firing. I've replaced the fuel pump last week because of low fuel pressure. The The ECM is from a Junk yard. The orig ECM was a #4482 so I replaced it with a #7747 ECM. I have noticed that the last couple of starts it would run rough until it warmed up then ran fine. Another intermittent problem is an idle issue, sometimes when in gear it will idle down to an almost stall then recover. It will do that when in neutral as well but not as extreme as when in gear. I'm thinking Its an ecm issue. The ECM looked old like it had been on the shelf for awhile had some rust stains on cover. I got it anyway because i needed it for a core and decided to try it out first before buying a reman ecm. The ecm prom is new from http://www.tbichips.com .I haven't checked to see if there is spark but will do that now. Will post results of the spark check. If anyone has any other ideas please chim in. :banghead:

I am interested in the spark check and also fuel pressure. I'm also curious as to how the inside of the distributor cap looks.

 

[Bertscova]

Ok there is no spark, Under the dizzy cap still looks new no signs of wear, Fuel pressure is 15 psi. The only thing that i can think of that could cause this problem that is not a new part is the ecm. No to say that one of the new part couldn't have failed but I'm leaning more towards the ECM. What are your thoughts.

 

[Bertscova]

It is throwing code 51 Faulty prom. The prom is new from tbichips.com I've sent him an email informing him about the problem. Just waiting on his response. One thing is I didn't pull the codes from the ecm before i swapped ecm so Will it set fault code if the engine wont start. Also could it be throwing this code because I just reinstalled the ecm and it hasn't run yet ???

 

[astro355]

It is throwing code 51 Faulty prom. The prom is new from tbichips.com I've sent him an email informing him about the problem. Just waiting on his response. One thing is I didn't pull the codes from the ecm before i swapped ecm so Will it set fault code if the engine wont start. Also could it be throwing this code because I just reinstalled the ecm and it hasn't run yet ???

No, the ecm would only throw that code if it has detected a problem with itself. In some books, it listed DTC 51 as a PROM error while in others it is listed as incorrect MEM-CAL.

 

[Bertscova]

See next post

 

[Bertscova]

OK I think I have found The Code 51 problem. In the Pic the socket circled, Is that were the MEM-CAL chip should be. I didn't get it from the core unit. I need to go to Advanced Auto First thing in the am to retrieve this. Another question, is the mem-cal data specific to the astro van or will a c1500 4.3's mem-cal data be the same (both are 1990) or should I get a mem-cal chip for a 1990 Astro with the 7747 ecm or do i need a 1990 c1500 5.7 mem-cal chip. I know there are alot of "or" here but remember My orig ecm was the 4288 ecm so i had to get a 7747 ecm. The one I got from the salvage yard was for a 1990 1500 4.3 so if there is a difference between astro and 1500 or 4.3 and 5.7 i need to know. from what I have read about the mem-cal it hold data for the boot up of the ecm so if there is a difference between 4.3 and 5.7 this could be the reason for the rough starts. I hope this post doesn't confuse you to much

 

[astro355]

That missing part will be a problem. Are you saying that it ran with that chip missing?

 

[Bertscova]

No i wont run without that chip. But I've fixed the code 51. Went to the auto parts store that has my core ecm and got that chip, Still wont start, but while i had the key in the run position to watch the check engine light, i noticed the IAC valve was making a noise and when i touched it, it was vibrating. Will a bad IAC cause no spark.??? The IAC has been a suspect for the intermittent idle issue's Ive been having.

 

[astro355]

IAC will not cause a no start. And in open loop, it should not be moving at all. I'm thinking its a problem with the ecm. I've never liked swapping chips out in them. You have to be really careful with that. You can have two ecm that are the same part number and if you swap the chips, things get 'funny'. There are so many different internal variations. I've always just swapped out ecms, not the chips. If a programmed a chip for a specific ecm, that's one thing. I just didn't swap a chip from one ecm to another.

 

[Bertscova]

I tried 2 ecm today both were remans and i put my performance chip in them both. and still no spark.when you buy a remanufactured ecm you have to swap the chip from the old into the new

 

[astro355]

I tried 2 ecm today both were remans and i put my performance chip in them both. and still no spark.when you buy a remanufactured ecm you have to swap the chip from the old into the new

That's odd. I have never had to swap a chip into a reman ecm.

Anyways, do you have any ecm with the original chip in it?

I also moved this topic into engines.

Jim

 

[Bertscova]

No I don't have any other ecm's . Thanks for moving this post. I"m thinking that its either the coil or the ignition mod under the dizzy. Waiting on msd tech support to tell me how to test the coil. I was on there web site and there are alot of problems with this coil i'm using. Its a msd # 8226. Not sure how to test the ignition mod under thi dizzy. Maybe someone knows how to test these parts

 

[astro355]

Which ignition module are you using?

 

[Bertscova]

I'm using the factory mod that came preinstalled on the new dizzy i got from napa

 

[Bertscova]

This one

 

[astro355]

Do you have another coil that you can try in place of that msd 8226?

 

[Bertscova]

I think i have the one from the 4.3. I was going to goto the u pull it in the am and get a couple coils they are only $5 there

 

[astro355]

If you have the remote coil from the 4.3L, that should work for this test. That is of course you know it worked before.

 

[Bertscova]

I know it work 3 yrs ago when the van was parked with a blown head gasket. I'm not even sure i still have it. Is there a way to test that mod