Measuring fuel pressure.

This is the place to discuss restoration problems, post questions or projects-complete or partial.
robhaynes
Posts: 25
Joined: Mon Jan 05, 2015 10:19 pm
Your car is a: 1980 Fiat Spider 2000

Measuring fuel pressure.

Postby robhaynes » Mon Jan 12, 2015 5:04 pm

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?

spider2081
Patron 2024
Patron 2024
Posts: 2967
Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT
Contact:

Re: Measuring fuel pressure.

Postby spider2081 » Mon Jan 12, 2015 11:22 pm

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.

vandor
Posts: 3996
Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: Measuring fuel pressure.

Postby vandor » Mon Jan 12, 2015 11:35 pm

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.
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town

robhaynes
Posts: 25
Joined: Mon Jan 05, 2015 10:19 pm
Your car is a: 1980 Fiat Spider 2000

Re: Measuring fuel pressure.

Postby robhaynes » Thu Jan 15, 2015 2:49 pm

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?

robhaynes
Posts: 25
Joined: Mon Jan 05, 2015 10:19 pm
Your car is a: 1980 Fiat Spider 2000

Re: Measuring fuel pressure.

Postby robhaynes » Thu Jan 15, 2015 3:44 pm

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.

viewtopic.php?f=6&t=4590

robhaynes
Posts: 25
Joined: Mon Jan 05, 2015 10:19 pm
Your car is a: 1980 Fiat Spider 2000

Re: Measuring fuel pressure.

Postby robhaynes » Tue Aug 30, 2016 9:06 pm

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.

spider2081
Patron 2024
Patron 2024
Posts: 2967
Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT
Contact:

Re: Measuring fuel pressure.

Postby spider2081 » Wed Aug 31, 2016 7:34 am

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


Return to “Restoration Projects”

Who is online

Users browsing this forum: No registered users and 44 guests