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Hard start on 90 K-5 Blazer **Problem SOLVED**

opfor2

opfor2

1/2 ton status
Joined
Oct 28, 2002
Posts
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Location
Ventura County, CA
**SOLVED**

Well today I removed the NEW IAC valve which I bought at Kragan Auto parts, it was a aftermarket "Niehoff" Part # 21738 and what did I fined when I removed the IAC. The pintle head gad somehow broken off and was stuck in the close position which is way I had a hard start and high or low RPM's. Lessen learned, “DON’T BUY CHEAP AFTERMARKET ****” Now my truck runs like it's brand new till the next thing to brake.
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Hi all,

Within the past three days I'm having a hard start problem on my 90 K-5 TBI w/350. :mad: :mad: :mad: I did a search of past articles and here is what happens. When I go to start the truck she just cranks and won’t start lick she used to. After about 5 to 10 seconds the eng will start but it idles like crap, but once running it runs fine.. I checked the fuel pump and I do hear it run for about 2 to 3 seconds then it stops so the fuel relay is ok. I cleaned the ground on the driver’s side frame that goes to the fuel pump. The fuel filter was replaced about 5000 miles ago so I don’t think it’s that. I have a OEM service manual and I checked the following tests:

* Hard start
* EGR system
* Fuel pump relay circuit diagnosis
* Engine cranks but will not run

All tests and diagnosis checked ok, I’m at a loss as what to do next. Some of the archived posted talked about a faulty oil pressure switch causing a hard start but I thought that that would only happen if the fuel pump relay went bad. Any ideas?

Thanks

Dan..

Additional Info:

I have already replaced the following: :mad:

ECM temp sensor
TPS
IAC
plugs
wires
cap
injectors
TBI
rotor

**UPDATE**

I just replaced the IAC valve but, I'm wondering if it's bad. This morning I had a hard start, drove about 5 miles to drop the kids off at school, The engine was warmed up to operating temp and she ran and idled like a champ. After I dropped Katherine off the truck stated right up BUT the idle was up to about 2000 RPM’s. The Rpm’s wouldn’t drop until I stopped the trucked and then restated it. I kept the original OEM IAC valve so I’ll switch it back and see what happens. This is becoming really frustrating

Dan..
 
Last edited:
Sounds like your doing a thurough check on everything.

I just wanted to add that my buddy's truck got hard to start right before his fuel pump went out. Finally, the last time.. it just didn't start at all. We replaced the pump, and back in buisness.

The pump may be working... but may still be on it's way out.

Something to think about anyway. Good luck.
 
I've been told that ignition modlues can be the cause of a long delay before starting. However, that may be a bit of a last resort, as they are a bit expensive.
 
oil

After a hard start does the exhaust have oil in it? Also is it a hard start even after it has been driven for a while?
 
I hate to say check the basics again, but its happened to me in the past.

Check firing order (I switched 2 plug wires on accident, it was a hard start but generally ran OK)

Check for vacuum leaks (Ive knocked those stiff plastic hoses loose before and didnt realize it)

Then go through the emission and fuel suff you didnt check, like MAP, ignition module, pickup, etc...

Also, [re]check the spray pattern on the injectors with a timing light.

Post up any findings

Good luck
-Randy
 
next time you have a no start situation hold your gas pedal to floor like you would when you start a flooded carb. engine. if it starts and idles like crap but then clears out i bet your idle air control valve needs to be cleaned or replaced.
 
txfiremank5 said:
Sounds like your doing a thurough check on everything.

I just wanted to add that my buddy's truck got hard to start right before his fuel pump went out. Finally, the last time.. it just didn't start at all. We replaced the pump, and back in buisness.

The pump may be working... but may still be on it's way out.

Something to think about anyway. Good luck.
Click to expand...

Well, i was thinking fuel pump too this is the original pump and the truck has over 122K on it. I just don't want to drop da tank. I think I might cut an access door in the rear bed and replace the pump that way
 
chevyjeff said:
next time you have a no start situation hold your gas pedal to floor like you would when you start a flooded carb. engine. if it starts and idles like crap but then clears out i bet your idle air control valve needs to be cleaned or replaced.
Click to expand...

I just replaced the IAC valve but, I'm wondering if it's bad. This morning I had a hard start, drove about 5 miles to drop the kids off at school, The engine was warmed up to operating temp and she ran and idled like a champ. After I dropped Katherine off the truck stated right up BUT the idle was up to about 2000 RPM’s. The Rpm’s wouldn’t drop until I stopped the trucke and then restarted it. I kept the original OEM IAC valve so I’ll switch it back and see what happens. This is becoming really frustrating :mad: :mad: :mad: :mad:

Dan..
 
kinda weird, but look at your fuel injector spray pattern, just had some weird stuff happen the past week with my truck, ended up being the injector, after the pump, relay, oil pressure switch and computer were replaced i might add. :doah:

Just a thought on something to look at
 
**SOLVED**

Well today I removed the NEW IAC valve which I bought at Kragan Auto parts, it was a aftermarket "Niehoff" Part # 21738 and what did I fined when I removed the IAC. The pintle head gad somehow broken off and was stuck in the close position which is way I had a hard start and high or low RPM's. Lessen learned, “DON’T BUY CHEAP AFTERMARKET ****” Now my truck runs like it's brand new till the next thing to brake.
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