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Need help!!

jrdtckr

jrdtckr

Registered Member
Joined
Mar 5, 2009
Posts
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Location
Idaho
Where to start? Ive got a 87 k5 and ive been dealing with this stupid problem for 3 years now, stumped 5 real mechanics, count less back yard mechanics and so on. So lets get right in to it. At start up it run idels and runs fine. When it starts to warm up it throws codes 42, 43 starts back firing threw the intake and most of the time dies when accelerating from a dead stop or at slower speeds. On the highway it doesnt like to go above 55 and u got to mash the pedal to the floor for about 30 sec to a min and the kick down stepes in and it moves forward faster but once u let ur foot off the gas its back to 55. And it has no balls going up a steep incline. So those r my issues, heres the stoy behind it.

The truck had a small fire due to a over heated trans off hyw 5. Most of the wires and everything was fine, just burned the conduit. The distributor cap and wires were gone and a few other wires. Took it down to the heads and replaced everything that was crispy and had the trany rebuilt. This is where the problem developed. Swaped out the oe tbi for the holley tbi to see if that would help and it didnt. Replaced every sensor threw out the years. The only one that help was the map sensor and that was just a little bit. Its been timed more times then i can count. Changed the fuel filter twice, same with the air. Knock sensor new and working. Replaced the electric spark control three times. And computers been replaced.

So if anyone out there can help i would greatly appreciate it cause im pretty much lost. Im station out in germany and the trucks out in ca with the fam so it might take a while for me to get someone to try something out for me on it. But im tired of spending my leave time trying to fix this problem instead of having fun with it and im ready to do some wheelin!!

Thanks
 
British Slave said:
I would guess it's trying to run a carb with the TBI system. I would guess the sensors are telling the computer things are out of wack and the computer is trying to adjust timing to compensate.
Click to expand...

The Holley he referenced is a Holley TBI replacement. I heard they are junk but I do not know from first hand experience.
 
OK, I missed the TBI after Holly. Backfire in my experience is advanced timing OR in TBI engines, the ignition module. I fought a similar problem till the module finally died and wouldn't fire at all. Replacement module wiped away all thoughts of selling the Blazer.
 
cuervo said:
The Holley he referenced is a Holley TBI replacement. I heard they are junk but I do not know from first hand experience.
Click to expand...
The new ones are OK, the old ones had injector issues!

jrdtckr said:
Where to start? Ive got a 87 k5 and ive been dealing with this stupid problem for 3 years now, stumped 5 real mechanics, count less back yard mechanics and so on. So lets get right in to it. At start up it run idels and runs fine. When it starts to warm up it throws codes 42, 43 starts back firing threw the intake and most of the time dies when accelerating from a dead stop or at slower speeds. On the highway it doesnt like to go above 55 and u got to mash the pedal to the floor for about 30 sec to a min and the kick down stepes in and it moves forward faster but once u let ur foot off the gas its back to 55. And it has no balls going up a steep incline. So those r my issues, heres the stoy behind it.

The truck had a small fire due to a over heated trans off hyw 5. Most of the wires and everything was fine, just burned the conduit. The distributor cap and wires were gone and a few other wires. Took it down to the heads and replaced everything that was crispy and had the trany rebuilt. This is where the problem developed. Swaped out the oe tbi for the holley tbi to see if that would help and it didnt. Replaced every sensor threw out the years. The only one that help was the map sensor and that was just a little bit. Its been timed more times then i can count. Changed the fuel filter twice, same with the air. Knock sensor new and working. Replaced the electric spark control three times. And computers been replaced.

So if anyone out there can help i would greatly appreciate it cause im pretty much lost. Im station out in germany and the trucks out in ca with the fam so it might take a while for me to get someone to try something out for me on it. But im tired of spending my leave time trying to fix this problem instead of having fun with it and im ready to do some wheelin!!

Thanks
Click to expand...
Your replacing the wrong part. You said ESC.

42. Fault at electronic spark timing circuit (sets when timing is set also, clear code and verify that it does not return.)
43. Low voltage at electronic spark timing circuit

These are EST. This is the module in your distributor. It is known to be a intermittent issue and still run. Some parts stores can check them but it must be done at least 3 times and if it fails any of those times it is bad.

You also fried stuff in that area so it should have been replaced. But it need heat disapating compound under it or it will over heat and fail. Also the screws that hold it down are the grounds which can be an issue.

The other part of this circut than can cause these codes is the pickup coil inside distributor, they are only $10 but need to dismantle distributor to replace. If it got that hot back there well then it needs to be replaced.

Since your time is an issue I would suggest a new distributor from GM, not one of the cheap knock offs out there. Maybe an MSD replacemet.

HTH!

Stationed in Germany? Are you in the military? If so thank you for your service to our country! :woot:
 
damn the holleys r junk huh? that sucks i wish i kept the original. but u think the module would help my case? cause the engine seems to be running strong its just whatevers ****ing up is giving me the headache. 350s are pretty easy to work on, but this is just confusing everyone.
 
ya ive replace the est about 3 times i think by now. and that didnt change a thing. but yes i was thinking the same exact thing last time i was home. i actually bought a msd dist. from summit while i was in afghanistan. wanted to make sure it was there by the time i got home. but it ended up being the wrong type of dist. i got the MSD-8360 and it had the wrong plug in the back. but yes i def still think a new dist is in order.

thanks a ton for ur advise i really appreciate it.

and yes im currently serving in the air force out in germany. i do miss home quite a bit though. thanks for the thanks, its all in a days work ha.
 
This is the proper distributor in MSD version. GM would be just as good.
http://www.summitracing.com/parts/MSD-8366/?rtype=10

Code 42 will set when you disconnect wire to set timing. Disconnect battery to clear codes.

43 low voltage? That could be the ESC? Have you replaced it? Or knock sensor but you said you replaced that. It needs to be torqued and the setting is not that high, I forget like 10 pounds if to tight the sensor fails and you will always have knock retard and fail Code 43 test.

Also go to this link and at bottom of page is GM Service Diagnostic procedure for all codes in a pdf. No reason to stump everyone, it is not rocket science, all you need is a digatal volt meter and read exactly how to test that circut.
http://coloradok5.com/forums/showthread.php?t=240425

Your in Idaho just bring it over...
 
alright i finally was able to the distributor on order. now i just got to wait for it to come in and find someone to install it ha. thanks again ill let u know what happens.

**** i wish i was still in idaho. that thing would be a beast and id be having some fun ha. what part of idaho you at?
 
Coueur d'Alene!

I hope it does the trick, it seems to be last overlooked part of the puzzle.
 
eagle mark said:
Coueur d'Alene!

I hope it does the trick, it seems to be last overlooked part of the puzzle.
Click to expand...

alright well after a YEAR of waiting, im finally going to make it home to see if this dist. is going to do the trick. excited and nervous. ha. any last advise???
 
What part of California will you be in?

Make sure ALL your ground connections are good. A faulty ground will really wreak havok on the ECM. Double check all the ground connections at the rear of the motor, motor to body, motor to frame, etc. Given that you had a fire, I would really advise focusing on your wire loom as a whole. Just as a bad ground can mess with your system, a short on any of the sensor wires can as well. Don't just check a sensor at the source and assume it is good. The sensor could be working, but the wire is burnt on rout to the ECM.
 
jrdtckr said:
alright well after a YEAR of waiting, im finally going to make it home to see if this dist. is going to do the trick. excited and nervous. ha. any last advise???
Click to expand...

Do all your guages and turn signals work correctly?
There is a ground on the driver side right about where the side vent is under the dash.
I had that come un-done and all kinds of wierd things started happening.

I think this is where the ADL connector draws it's ground from.
 
nsxxtreme said:
Do all your guages and turn signals work correctly?
There is a ground on the driver side right about where the side vent is under the dash.
I had that come un-done and all kinds of wierd things started happening.

I think this is where the ADL connector draws it's ground from.
Click to expand...

Ya all the gauges work except the oil pressure. But I think that's just the sensor. But I'll def check it out. Thanks.
 
Interested to hear what fixes this....

Sounds like eaglemark is on it, all fingers point to that est/distributor, especially with the fire and all.
I'd be interested to see what the vacuum is reading in that manifold, especially if your distributor is vacuum advance.
Good luck. :thumb:
 
Alright got the dist in and timed multiple times. Runs like a champ at idle. As soon as you put a load on it, it starts acting a fool and studering and everything. Any ideas??
 
Keitha said:
What part of California will you be in?

Make sure ALL your ground connections are good. A faulty ground will really wreak havok on the ECM. Double check all the ground connections at the rear of the motor, motor to body, motor to frame, etc. Given that you had a fire, I would really advise focusing on your wire loom as a whole. Just as a bad ground can mess with your system, a short on any of the sensor wires can as well. Don't just check a sensor at the source and assume it is good. The sensor could be working, but the wire is burnt on rout to the ECM.
Click to expand...


im over in the east bay in dublin. were going to play with the electrical tomorrow.
 
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