Page 1 of 1
Measuring fuel pressure.
Posted: Mon Jan 12, 2015 5:04 pm
by robhaynes
I figured out my 1980 2000 had a bad fuel pump so I replaced it. Now, it starts and runs for a few seconds and quits. If I disconnect the cold start valve, the car will just crank and not start. So, I'm thinking its just running on what the cold start valve squirts in there. My next thought is to do some diagnosis. I want to hook up a fuel pressure tester to the rail and see whats going on. My wonderful home shop manual for the car just says "don't try this at home".
So, how are you hooking up the tester? I don't see any test ports. I was thinking I'd take off the fuel hose from the cold start valve and plug it into the tester. Do you put in a test port with a schrader valve? The bottom of the fuel hose is press fit somehow onto the rail. Do I just cut it off there to replace it with a new hose and hose clamp? I know I need the high pressure type of fuel hose.
Also, I want to put the injector in a jar and see how it squirts. Any tips about the best way to do this?
Re: Measuring fuel pressure.
Posted: Mon Jan 12, 2015 11:22 pm
by spider2081
I purchased a Fuel Pressure test set at Harbor Freight
http://www.harborfreight.com/fuel-injec ... 92699.html
Purchased a 3 foot section of FI hose from local auto store and a 5/16 -5/16 hose connector.
I disconnect the cold start valve insert the 5/16 connector into the hose for the cold start valve then connect the gauge with the 3 foot hose.
There is a circuit in the ECU that could be your problem.
Re: Measuring fuel pressure.
Posted: Mon Jan 12, 2015 11:35 pm
by vandor
Why do you want to test the fuel pressure if the car starts on the cold start valve?? Obviously there is pressure.
Sounds like the electrical part of the FI is not working. There is a Fuel Injection Diagnostic manual, that would be very useful. I think it may be on Brad's website?
http://www.artigue.com
The first thing I would check is that the wire coming from the FI harness on the passenger side of the engine compartment is connected to the negative side of the coil, and the connection is good and tight. That is where the FI system gets the signal to fire the injectors.
Re: Measuring fuel pressure.
Posted: Thu Jan 15, 2015 2:49 pm
by robhaynes
vandor wrote:Why do you want to test the fuel pressure if the car starts on the cold start valve?? Obviously there is pressure.
Sounds like the electrical part of the FI is not working. There is a Fuel Injection Diagnostic manual, that would be very useful. I think it may be on Brad's website?
http://www.artigue.com
The first thing I would check is that the wire coming from the FI harness on the passenger side of the engine compartment is connected to the negative side of the coil, and the connection is good and tight. That is where the FI system gets the signal to fire the injectors.
I followed the diagnostic manual and got to page 12 where the procedure ends and it says "replace the control unit" after checking to make sure various voltages are present on the connector pins. Its an expensive part, are there other ways to insure that this is the part I need to replace?
Re: Measuring fuel pressure.
Posted: Thu Jan 15, 2015 3:44 pm
by robhaynes
I found this thread, but the resolution didn't work for me. It seems that this is a common problem and rarely is the the ECU. Any other threads you can point me at would be helpful.
http://www.fiatspider.com/f08/viewtopic.php?f=6&t=4590
Re: Measuring fuel pressure.
Posted: Tue Aug 30, 2016 9:06 pm
by robhaynes
Just to follow up on this thread to conclusion. This issue was clogged injectors. I took it to one of those clean-and-test places. When I went to pick it up, they said they cleaned them but couldn't test because they didn't have the right adapter so they didn't charge me anything. I put them back in and she started right up.
Re: Measuring fuel pressure.
Posted: Wed Aug 31, 2016 7:34 am
by spider2081
That's great. Just a thought. If your fuel pump failed and your injectors were clogged you might be getting contamination from you fuel tank into the system. Do you have a filter installed before the fuel pump. Some of us feel it is worth installing to give the pump some protection. The filter I use is a Wix pn 533248 Napa # 3248