im at my wits end with my 89 k2500 need some help.

[topumpchump]

I have a 1989 k2500 5.7 tbi with 171,xxx miles on it. I've had no issues with it until a month ago when the engine is under load it cuts out, as soon as I let off it back fires and everything is normal. I've replaced cap and rotor, plugs and wires, coil, egr valve and solenoid, map sensor, tps and fuel filter trying to track down the culprit. Ran the codes, it came back with code 34 map sensor. Unsure why, cleared the codes and it throws it again. The truck idles just fine just won't drive well.

 

I should probably also include that the truck has no cat anymore and is 3" straight pipped back to a flowmaster. Unsure if that will make any difference with help as it had had this set up for over a year prior to any issues. Please help, I'm not used to these tbi systems but more familiar with old school engines that only need suck, blow, bang to run correct.

[topumpchump]

**UPDATE**

 

The problem has been solved. Turned out the ignition control module was fried. Replaced it and in runs like a champ again.

[topumpchump]

I've checked for vacuum leaks and the condition of the hoses. No leaks, cracks rotting ect. The map sensor is brand new. And the second one to make sure the first one wasn't a dud. There is still an o2 sensor up on the y pipe. We just cut the cat and replaced it with a straight pipe. The cat was way plugged.

[ChevyTech77]

Fuel filter on backwards? You've got to be kidding me? They only flow one direction and if you screw that up. You shouldn't be allowed to drive let alone work on a vehicle. For the last time I've checked grounds, vacuums and harness. Its no longer throwing any codes yet still have the issue. I'm thinking its timing or possibly a sensor I've missed.

 

Any legitimate help would be appreciated. Read the post and replies and I'm sure you'll see what I've don't on countless occasions.

 

Thank you.

 

You're kidding me, right? There has been PLENTY of legitimate help in this thread yet you continue to just shotgun parts at this truck and then go off about people not knowing how to work on a vehicle and giving you bs help?

[topumpchump]

Yes there has been a lot of help. But shotgunning parts is quite an understatement. Do you really think this is the only forum I've posted to? No would be the answer.

Assuming that making such a rookie mistake as the fuel filter or a ground that I've been over about a dozen times is quite insulting, not to mention annoying.

The legitimate help has and is well appreciated and had made a difference in the overall operation of the truck. Your snide remarks however, have not.

[bossier62guy]

My dad's 89 had exactly the same problem.....pulled the bed off, pulled the fuel pump out of the tank, a short piece of rubber hose that was part of the pump assy had deteriorated and had a slit in it. We replaced that short rubber hose and it fixed the problem. That was about 2 years ago. BTW, his was a 1500 series but an HD model w/ the 5.7.

[topumpchump]

Yes the truck runs great while in neutral. Idles great. Can ouch the throttle with no stumble. Just when in gear and under load does it act up.

 

Punch the throttle *

[topumpchump]

I've already done a vacuum test and replaced the map sensor. Lines all look good as well. Tps is also new. Both seemed to help the truck, but not fix the drivability of it. Also still runs really rich.

[hidefmike]

This is all cute and all but am I the only one that finds it hard to believe that a fried ignition module caused this problem? I'm no ex GM tech like govtech4 but I don't see how it was running at all. Nonetheless it's nice that it's fixed and you have a slew of brand new parts in it. Cheers and I'm done.

 

/\ /\ Agree 100% /\ /\

 

I think the problem was a combo of electrical problems, IM was the last piece that needed to be swapped. It is odd that the IM was malfunctioning, and not completely dead. My experience has been these just quit, and they done just start to die. BUT, It is electrical, and on a TBI engine so anything is possible.

 

On the bright side, all he needs now is a new long block and the engine will be brand new!

 

 

Sent from my iPad using Tapatalk HD

[hidefmike]

Check the coolant temperature sensor. Buy an OE one. Since you've changed all the other sensors, it can't hurt.

 

I had the exact same problem you had, engine flooding under load. CTS fixed it.

[topumpchump]

I'll be replacing that this weekend and that hose did come with the new one. I'll be sure to examine it all before it goes back in the tank.

[Jsdirt]

At this stage, I'd be really pissed. I go to the extreme when that happens, but it usually resolves the problem for good.

 

Grab an Edelbrock intake & carb., install, and sell all the electronic dodads on eBay.

 

FIXED.

[txab]

top,

 

Lose the attitude. You'd be surprised how many people make simple mistakes or overlook obvious things when trying to track down a problem. We have no idea what your level of experience is. So quit getting bent out of shape, unless you want people to start ignoring you because of your 'tude.

[topumpchump]

I've been really tempted to pull all the injection shit off and slap a Carb on it and call it good. But that's the reason why I bought the truck. Better MPG then my 2 other trucks I got rid of. I had a 85 s10 blazer with a v8 swap running premium and only getting 8 MPG and a 70 el Camino doing about the same. I'll try to sensor and hope it helps. By the time it does work properly I'll have a brand new truck made over 20 years ago.

[Jsdirt]

With some patience you can get a carb to pull some real surprising MPG numbers. Was talking with a guy at a car show years ago that drove a 32 Ford coupe with a supercharged Chevy 350 with dual quads and a 700r4 tranny - claimed he got 20 mpg driving it there from NY. This was in Worcester, MA!

 

My '89 S10 Blazer's engine started life in a '00 Jimmy. After repairing a check engine light PER WEEK for 2 years straight, I parted the truck out, threw the spider in the trash, slapped a carb & intake on the 4.3, & dropped it in the '89. Best thing I ever did. Gets 16.5 MPG with 3.73's, dedicated snow tires, crappy winter blend fuel, and 4x4. Can't complain. It went from a failure prone unreliable piece of ****, to a dependable daily driver that has better power, throttle response, and starts instantly.

 

I like being able to repair it with a screwdriver instead of a laptop.

[gmtech4]

id throw that crap in the garbage and do as smitty said ......you have hemmoraged money and it has to stop !!!

 

my 2 cents