hot start problem
08-07-2007, 04:43 PM
#1
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hot start problem
hi there
My 91 20 valve is having infrequent hot start problem. If i start the car up shortly after shutting it down (running into a store) it will not idle. It starts but dies right off unless I give it some gas. The fuel pump has been replaced within the last year. Do you think it can be the fuel pressure regulator? how would I check that?
thanks
My 91 20 valve is having infrequent hot start problem. If i start the car up shortly after shutting it down (running into a store) it will not idle. It starts but dies right off unless I give it some gas. The fuel pump has been replaced within the last year. Do you think it can be the fuel pressure regulator? how would I check that?
thanks
08-07-2007, 05:35 PM
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When you say replaced the fuel pump which did you use?
Normally I see a slight variation of this on V8's...but after that trip to the store the car will usually not start at all till at least 30 minutes or so.
Mimic this by getting the car hot & this time pull in your driveway. Pour some cold water on the driver side trans bellhousing. There are 2 sensors down there. One controls the ign, the other controls the rpm. If the car starts fine after replace the ign sensor.
All so this is a classic symtome of a bad check valve on the fuel pump.
Fuel pressure reg could be the culprit as well.
Mimic this by getting the car hot & this time pull in your driveway. Pour some cold water on the driver side trans bellhousing. There are 2 sensors down there. One controls the ign, the other controls the rpm. If the car starts fine after replace the ign sensor.
All so this is a classic symtome of a bad check valve on the fuel pump.
Fuel pressure reg could be the culprit as well.
08-07-2007, 06:21 PM
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Re: hot start problem
As Ron asks, did you use the newer, smaller diameter fuel pump for the replacement, or did you replace with the older style that had a pressure damper (item # 34 in pix) on top of the banjo bolt fitting on the pump?
The new, smaller pump has an integral pressure damper, and I've not heard of any problems with them. The older external dampers are known to fail and your symptoms are some of what can happen with a failed one, as MiB says.
The new, smaller pump has an integral pressure damper, and I've not heard of any problems with them. The older external dampers are known to fail and your symptoms are some of what can happen with a failed one, as MiB says.
08-08-2007, 01:01 AM
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Re: When you say replaced the fuel pump which did you use?
Ron, he says car starts but dies. He has to hold the gas to keep it alive, if I'm reading right.
I'd look at some idle control areas. ISV, etc.
I'd look at some idle control areas. ISV, etc.
08-08-2007, 06:24 AM
#6
Re: hot start problem
If you think you are having a problem with leak down of the fuel pressure try installing the fuse int he FP relay and turning the key on for 10 secs prior to attempts to start. This will allow the FP to build pressure. If it works tyou have a leak down issue. Either a check valve or leaky injectors.
08-08-2007, 12:26 PM
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If it's not a flakey ign ref sensor I would think you have to start with a flow test...
....that would rule out a fuel issue.
But these symtoms are classic ign ref sensor...or check valve on the fuel pump.
As I all so mentioned & Mr buggy mentioned..could be the fuel pressure accumulator not holding enough pressure but when he rev's it up fuel flows fine.
Inj could be leaking out. Spray some WD40 were the inj enter the head...you'll be able to tell if the inj seals are bad.
Mr buggy, have you checked Chris Miller's 20v web site..or SJM's web site?
But these symtoms are classic ign ref sensor...or check valve on the fuel pump.
As I all so mentioned & Mr buggy mentioned..could be the fuel pressure accumulator not holding enough pressure but when he rev's it up fuel flows fine.
Inj could be leaking out. Spray some WD40 were the inj enter the head...you'll be able to tell if the inj seals are bad.
Mr buggy, have you checked Chris Miller's 20v web site..or SJM's web site?
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08-08-2007, 06:28 PM
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the car starts but will not hold idle, i need to give gas to keep it alive
I used the smaller diameter pump. I needed to get the little plastic fit kit in order to mount up to the tank. I will check the ign ref sensor. thank you for your replies so far, keep the suggestions coming.
cheers
cenk
cheers
cenk
08-09-2007, 04:02 AM
#9
A failing crank ref usually results in a no start condition.
Sounds to me like your A:F is off. Check temp sensors and O2 sensor. The O2 sensor voltage should be changing as the ECU atempts to keep the A:F steady it will run slightly rich to slightly lean and keeps oscillating. A steady voltage indicates a shot O2. There is plenty of info regarding temp sensors. Search the forum for more on them.