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Really rough start... fuel problem?


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Hey... I have a 1990 Pioneer 4.0 4x4 auto. I am having some trouble getting my comanche back online and running correctly. So far I have replaced.... the coil, plugs, wires, gas tank, and fuel filter. I get some pressure (39) when I initially turn the key, then it bleeds off.... It will start but at very low rpm and the OIL PRESSURE light is on. I put a little gas in the intake and the rpm's increase. I think that I am having issues with either the fuel pressure regulator or something to do with the fuel pump. How do I test both? Is there anything else that I may be missing?

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Let's see. You posted a question at 10:15. At 10:28 you're getting agitated because nobody has answered yet. 13 minutes. C'mon fella. Get real. People don't sit at their 'puters 24-7 waiting to jump on questions. Yes you have a problem and it's aggravating but but don't get unreasonable about it. OK? If you had a Haynes repair manual you would find the information you need on page 4-2.

i. your going to need a fuel pressure gauge. Don't have one? Most parts stores have one to loan.

2. Could be a clogged fuel filter. They're easy to check. Just because a filters new doesn't mean it's good.

3. The number your looking for is around 40PSI.

4. based on given info I think the regulator could be the culprit.

Could also be faulty injectors.

 

You will find this forum has some of the most knowledgeable people around and are more than willing to share their knowledge and experience, but jeez guy. Be reasonable. Jim

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Actually he waited a week before asking again.

 

Well, 7 days and thirteen minutes to be exact, but who's checking?

 

As to the problem I would look to somethig causeing a flow restriction, possibly the fuel filter. If your pump is putting out 39psi of a reccomended 40 then it seems to me your pump is working, though it might be having issues keeping up with the required volume.

 

I would check/replace the filter and go from there.

 

~Brad

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Thanks! I have a new fuel filter... but i may check it out again. I have a pressure guage and I tested it, that is how I know that it bleeds off. I am in the process of changing the pressure regulator. I will let you know what I find out.

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Changed fuel pressure regulator and is running better... when I push on gas petal it cuts out.... I can put gas in intake and rpms go up... I am gonna have to check fuel pump, but the pressure stays around 40 so I still don't know!!!!!!!! any more ideas....?

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It will read 40 when you first start the motor but then should drop to 31psi. Is that what yours is doing or does it go below 31? With the engine warm and running the pressure should be 30-31psi. 40 psi is what you should get with the vacuum line dis connected from the regulator. Might hook a vacuum gauge in the line going to the regulator. See what it does when you step on the gas.

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Not real sure what it is... I have checked all the lines that I can see. I will look up int the manual to find any others.... It almost sounds as if there is a miss fire. I am thinking maybe the injectors may be clogged up.... or might be a sensor????

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Pull your plugs. Read them. Almost every shop manual has pics of what they should look like. With todays high output ignitions that is not as accurate method as it was in earlier days but sometimes it will still give you a clue. Just see if one is different from the others in any way. Color, soot, carbon etc. That will at least narrow it down to one cylinder.

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  • 4 weeks later...

IT WAS THE CPS AND INTAKE GASKET!!!!!!!!!!!!!!!! RUNNING GREAT!!!!!!!!!!!! NOW all it need is some new break lines and a set of 2 rear leaf springs.... ANYBODY HAVE A SET THAT IS CLOSE TO PA????? THANKS FOR ALL YOUR HELP!!!

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Sorry,but I need to jump in here and ask something.

 

Is the cps on the driver's side on the bell housing?

 

And do all '87's have one?

 

I expect on answer to my question in the next 30 secs or else! :mad: ...lmsoa

 

Thx,

 

Ron

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