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TXredfish · 11-09-2013, 03:11 PM

Original problem - engine was missing very bad and would die until warmed up, then ran great. I cleaned the MAF. Same problem occurred. After warming up, I drove a 60 mile round trip just to try out. It ran great. Let the engine cool down overnight. Same problem, hard to start and running very rough until warmup. I had to keep foot on the gas and rev up the rpms to keep running. Then I cleaned the air throttle intake. Now the engine will not start all. It tries but will not start. It backfired a couple of times. But no starting at all. Could the spark plugs be carbon up and be the problem? I tried to pull plugs but could not get out due to heat shields.
How do I get the plugs out? Also do you think the input throttle (drive by wire type) be the original problem? Is there any way to trouble shoot the input throttle or just replace?
Any ideas ................

gauto5150 · 11-09-2013, 03:43 PM

If you hold the pedal down when you're cranking, it should put the computer in "clear flood" mode. That shuts down the injectors when the computer recognizes wide open throttle upon low rpm cranking.
However, I'm assuming you have the 8.1 liter engine? The upper intake plenum has issues with the sealing of the intake gaskets causing rough start when cold.
Do you have engine codes? A check engine light?

Argosy · 11-09-2013, 04:13 PM

You need to put a scan tool on it and find out what is going on. Something as simple as a bad temperature sender can cause the computer to think it is below zero and pour fuel into the engine to get it running. Without some trouble shooting everything is a guess.

TXredfish · 11-09-2013, 05:57 PM

8.1L engine. Before, when it started but had trouble running, I had over to my mechanic. But when there, it ran fine and no codes. It did sit there for a couple of days before using the scanner. Brought it home, drove 60 miles, rough starting but when warmed up it ran fine. Now after cleaning throttle body it just turns over but will not start. I must have done something while cleaning throttle body. It started before cleaning, but ran rough at startup. Like I said I to keep my foot on the gas pedal and rev up RPM to 1500. After warmup it ran fine but now after cleaning throttle body it will not start at all. It just turns over but tries to start but will stay.

gauto5150 · 11-10-2013, 08:40 AM

Hold the throttle wide open while cranking, it's probably flooded from the cleaner and the fuel.
It really sounds like your intake gaskets are bad. I've replaced many of those with the same symptom at work.

TXredfish · 11-10-2013, 01:37 PM

gauto5150,
The intake gasket you refer to, is this the gasket that the intake throttle body sets on. At least it was starting before I cleaned the intake throttle body.
Now, it only turns over, no start................

Argosy · 11-10-2013, 03:26 PM

Have you pulled any plugs to see if they're fouled?

Brazel's RV Performance · 11-10-2013, 06:46 PM

I'd recommend replacing the MAP sensor.

spritz · 11-11-2013, 08:13 AM

We have been having the same problem with our MH we changed the plugs last spring everything was fine started fine ran on high idel and kicked it down and ran smooth. Now a few weeks ago we changed the plug wires and it ran sooo much better. Now that it has cooled off upper 20's to low 30's a bit it is doing the same as the OP stated. I had my neighbor come over and he said that it is the choke pull off. If I hold the butterfly open it smooths right out and idles fine if I don't it starts rough. I am going with what the neighbor says its only 18-25 bucks for a new pull off. I hope that does it.

Tim

TXredfish · 11-13-2013, 12:23 PM

I pulled one of the plugs. They appear to be fouled to a point that I could see a burn streak from the center to ground, as if shorting out. I will try changing the plugs. Maybe the intake throttle body cleaner got on to the plugs and shorted out. I still think I have a problem with the throttle body.
But not sure .............

macantic · 11-13-2013, 01:21 PM

Quote:

Originally Posted by Argosy

You need to put a scan tool on it and find out what is going on. Something as simple as a bad temperature sender can cause the computer to think it is below zero and pour fuel into the engine to get it running. Without some trouble shooting everything is a guess.

X2 on that!

TXredfish · 11-16-2013, 07:30 PM

My mechanic put his scan tool on my engine. It did not show any codes. But disconnected the MAF and still no codes. So he is not sure if his scanner is compatible with the chevy 8.1. He uses the scanner on some of the larger GM trucks with 8.1 but not sure if something on Workhorse MH would be different. A spark plug was pulled and had gas on it. The spark plugs are not firing because it appears that something is just pouring too much gas into engine. Engine just cranks over. Will any of the fuses such as Mass Air/Oxy sensor, electronic throttle module, etc cause this problem? He is suspecting the throttle control but not sure and does not want to just throw parts at it. He is going to discuss this with his scanner manufacturer to see if he can get updated software before trying again or he may try another scan tool that he has, this Monday. Anymore ideas?

TXredfish · 11-16-2013, 07:37 PM

My mechanic did say his scan tool showed that the temperature sensor showed 65 degrees and was OK. GAuto5150, what intake gaskets are you referring?
I will mention to my mechanic as that is being a possible problem.

gauto5150 · 11-19-2013, 07:21 PM

The plastic intake manifold assembly bolts to the intake side of the cylinder heads. The gaskets where those 2 mate is what I'm referring to.
Let us know if you get it fixed!