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

topumpchump

By topumpchump
in Ask A GM Technician

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topumpchump Enthusiast

topumpchump

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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.

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topumpchump Enthusiast

topumpchump

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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 Enthusiast

hidefmike

Posted
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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.

Jsdirt Senior Enthusiast

Jsdirt

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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. :thumbs::cheers:

topumpchump Enthusiast

topumpchump

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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 Senior Enthusiast

Jsdirt

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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. :D

gmtech4 Senior Enthusiast

gmtech4

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

 

my 2 cents

topumpchump Enthusiast

topumpchump

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The thing starts and runs every time. No problems there. No hard start or miss fireing. Just when the engine is under load is when I have issues. Id like to keep the injection if possible. I've already dumped enough money in to it. There can't be too many more things I can do to find the issue.

topumpchump Enthusiast

topumpchump

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I was pulling about 21 MPG in town with the truck before this all happened. Its really low geared so highway driving its less.

ChevyTech77 Senior Enthusiast

ChevyTech77

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What is the vacuum reading AT the map sensor?

 

Are all the engine harness grounds good and in the correct location? Lots of missed engine to frame grounds and all the harness grounds put on the same thermostat housing bolt, etc causing weird issues with these engines.

 

If the 34 is still setting you have to properly diagnose the cause for this code and resolve it before going any further. Just chucking parts at the thing isn't going to always fix it, period. Sorry.

Badass69 Senior Enthusiast

Badass69

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What about actual mechanical problems. You should see it on the vacuum gauge but at 170 some thousand miles a timing chain or worn out distribtor could be just as likely at this point.

Badass69 Senior Enthusiast

Badass69

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Did you pop a brand new distributor in the truck at the same time? This very well could be ignition related.

aflesch Enthusiast

aflesch

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Just because you have good vacuum and a good MAP sensor doesn't mean that the signal is actually getting to the ECU.

you need to get a pinout of the main ECU connector and back probe the MAP sensor wires to make sure the signal is getting there.

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