PIP and/or TIF problem?
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Tuned
Joined: Aug 2007
Posts: 287
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PIP and/or TIF problem?
1988 F250 351 2WD
My truck is starting then cutting out 10 times before staying running and then not well. I've read many of the recent posts about fuel pump switch/fuel pump operation and testing and the function of the PIP to give the correct signal to the ECU that the truck is running. So this is what I tried.
I jumpered the yellow and brown at the fuel pump switch and the pumps ran continuously. Leaving the jumper in place I started the truck. The truck ran for 5 seconds and then cut out and the fuel pumps continued to run until I disconnected the jumper. The fuel pressure remains consistant around 35 PSI before, during and after. The only thing I can think of is a defective PIP/TFI.
The confusing part of this is that the distributor and TFI are remans. from Advance less than 2 months ago. They said they can get me a replacement by Friday. Todate I have also replaced the ECU, and all three fuel pumps and the ECU relay.
Is there any other testing that needs to be tried prior to getting the new distributor/TFI?
My truck is starting then cutting out 10 times before staying running and then not well. I've read many of the recent posts about fuel pump switch/fuel pump operation and testing and the function of the PIP to give the correct signal to the ECU that the truck is running. So this is what I tried.
I jumpered the yellow and brown at the fuel pump switch and the pumps ran continuously. Leaving the jumper in place I started the truck. The truck ran for 5 seconds and then cut out and the fuel pumps continued to run until I disconnected the jumper. The fuel pressure remains consistant around 35 PSI before, during and after. The only thing I can think of is a defective PIP/TFI.
The confusing part of this is that the distributor and TFI are remans. from Advance less than 2 months ago. They said they can get me a replacement by Friday. Todate I have also replaced the ECU, and all three fuel pumps and the ECU relay.
Is there any other testing that needs to be tried prior to getting the new distributor/TFI?
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
I would say if your fuel pressure remains consistent around 35 PSI before, during and after then that is your problem.
You either have a vacuum problem, hose or a bad fuel pressure regulator.
Vacuum should change and as result the fuel pressure should change.
Normal fuel pressure should be around 32-34 (15-20 in) at idle and 42psi (5-10 in) at WOT. And with the engine off about 42-45psi (0 in) with pin #6 grounded of the test connector and the key on.
I think you jumpered at the Fuel Pressure Relay and not the switch.
You either have a vacuum problem, hose or a bad fuel pressure regulator.
Vacuum should change and as result the fuel pressure should change.
Normal fuel pressure should be around 32-34 (15-20 in) at idle and 42psi (5-10 in) at WOT. And with the engine off about 42-45psi (0 in) with pin #6 grounded of the test connector and the key on.
I think you jumpered at the Fuel Pressure Relay and not the switch.
Last edited by subford; Nov 21, 2007 at 11:30 AM.
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
Pull the codes, it should store something if it's loosing the PIP signal. www.fordfuelinjection.com
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Tuned
Joined: Aug 2007
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I will pull the codes again. I was a bit unclear when I related the fuel pressure situation in my previous post. More accurately, with the KOEO the pressure is about 40PSI. For the 5 seconds or so that the truck starts before dies, the pressure drops to 34PSI. As soon as the truck stalls, the pressure goes back up to 40 PSI. I just changed out the FPR yesterday, admittedly with a used FPR but it came out of the same year truck, was a Bosch, and had the Ford logo stamped on it to boot. Same exact PSI reading on the old FPR too. And yes I jumpered the fuel pressure relay right next to the ECU relay. This time I jumpered test pin #6 to ground.
As an aside, do you know what the third relay that is on the drivers side that on my truck is grey/black and is screwed to top edge of the fenderclosed to the firewall. It has 5 wires going to it. A heavy gauge brown, two blacks, a black with white stripe, and a yellow or maybe tan with a red stripe.
So now to repull the codes
As an aside, do you know what the third relay that is on the drivers side that on my truck is grey/black and is screwed to top edge of the fenderclosed to the firewall. It has 5 wires going to it. A heavy gauge brown, two blacks, a black with white stripe, and a yellow or maybe tan with a red stripe.
So now to repull the codes
Thread Starter
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Tuned
Joined: Aug 2007
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Likes: 1
ECO: I still need to get back to you for the overlay. That said, the Monitor gives me feedback on the PIP on pin #56, right? I'm not sure if my Monitor is working on the RPM scale. It only seems to read on the DVM scale in manual test mode or on the Hz scale if in auto test mode.
Other than that, the code I just pulled was 95 - "fuel pump secondary circuit failure - PCM to ground".
Where do I look for that ground - down by the fuel pumps or in the engine compartment?
This truck gave me only minor problems for 19 years. Then I changed the old worn out engine (186,000) and all hell breaks loose. I think I've changed almost every component and things are still screwing up. I guess it's making up for lost time.
Thanks
Other than that, the code I just pulled was 95 - "fuel pump secondary circuit failure - PCM to ground".
Where do I look for that ground - down by the fuel pumps or in the engine compartment?
This truck gave me only minor problems for 19 years. Then I changed the old worn out engine (186,000) and all hell breaks loose. I think I've changed almost every component and things are still screwing up. I guess it's making up for lost time.
Thanks
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Trending Topics
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Originally Posted by eco
You need one of these (subford, no it is not a waste and yes it does things that the NGS wont)...
I do not think that you understand what I was saying.
I love test equipment. I have a lot of it and go to Ford dealership auctions and buy Ford Special Tools whenever I can.
What I was saying is it does not make much sense for someone who does not work on trucks a lot to buy this kind of equipment that cost more than their truck did. Almost all problems can be solved in other ways without putting out this kind of money. Most if not all test equipment will only work well in the hands of someone who has used this piece of equipment on a lot of trucks. In other words it takes some interpretations of what the tester tells you, nothing is cut and dried. When they make one tester that will tell you 100% of the time what is wrong, then trouble shooting will be a thing of the past. You also should have a very good knowledge of how the system works to use the testers right to find the problem.
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