i'm having problems with a 1999 lariat with the 5.4 ltr engine. the truck has been flooded,i,ve rewired it and put in a new computer but there is stil a problem. after turning on the ignition, the injectors will havepower vor about 5 seconds, then they turn of again. Have tried all kinds of things but can't find where it comes from pherhaps the antitheft system has been triggered buthow can i get passed that and where do i find it. is there anybody who can help me out?

 

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Supply power should be at the injectors all the time while the ignition is on. The computer fires the injector by "grounding" the other side of the coil. Clarify if you've lost supply power to the injectorsor if teh computer has stopped firing them.

The "THEFT" indicator is your guide to what the PATS system (if equipped) is doing. Tell us what it is doing.

Steve

 

The injectors will become power for about 10 or 20 seconds, then there is no power anymore on them. I have no idea if the vehicle is equiped with a PATS antitheft system, it has been imported to europe with the flooding damage and insurance papers, but not with the owners guide and so. The only problem it has now is that te injectors keep loosing power, i've got it running on LPG (Liquid Petrol Gas)now because this will pass by the injectors,but it has got to run on fuel also.

 

Wel a year has gone by now, and the lariat has been standing in the corner for all that time and still has the same problem. think it is time now it should run normal on fuel and not only on LPG, but i keep having the problem. just a few seconds power on the injectors and then---> nothing, what ever i try, no more power supply on the injectors. as stated before, this car was flooded in Florida while putting a boat on a boat trailer and was sold y the inssurance company. I have exported the car from the USA to the netherlands (europe) and have been trying to get it running but it stil won't run normal. Is there anyone who has a clue for me?

 

Are you checking the injector power with a noid light or a meter. You need a noid light to see if they are actually firing while cranking.
I would check all of the grounds. battery to engine, battery to body and engine to body. A bad ground will do crazy things to a PCM.

 

You need to find out how the system works before you can find out what the fault is.
The LPG and Gasoline fueling systems are almost completely seperate.
The LPG fuels the engine thru special sleeve ports in the injectors. The injectors do not meter the LPG like they do for gasoline.
The LPG is already fuel regulated from it's own tank and is why the engine runs for you indicating the engine it'self has no faults.
When that supply runs out, THEN the gas injectors are broght on line by the PCM to meter gasoline in the usual manner.
At this point I can't tell what problem you have until you actually see what is or is not happening.
Being concerned about fuel injector operation when there is an LPG supply may be fooling you somwhat.
I done a quick look at an 02 system and would believe that there is not much difference in the basic operation from a 99 except for possible upgrades over time.
Trying to help thru this meduim is a difficult task if you have nothing to go with for info and trouble shooting for reporting the results.
This is at least a start to solve for the unknown.
It may be that there is not much of a problem once you get into the mechanics of it.

 

well a few months further now and still got the same problem. Power is always there on the injectors, they just dont become grounded so they wont inject fuel. Cleaned out al the ground wiring. but no result. Somehow there.s no signal from the cpm for running. I still think the pats anti theft system is not giving it free. Found a purple white wire going in to the pats system, but can not find this one going out to bypass it. anyone got a schedule of this systems wiring??