1998 cobalt 7.4 volvo fuel injected

[GRANGER65]

Re: 1998 cobalt 7.4 volvo fuel injected

i am certainly no mechanic, but i have owned my own shop peviously and have done ground up restorations including engine rebuilds etc. but the reason i am getting no fuel pressure is because for some reason the fuel pumps are not coming on unless i use a jumper wire where the 2 fuel pressure relays go. the seloc manual tells me to jump a wire from terminal 85 to i believe t was 87. when i do this the fuel pumps work. i can actually crank the engine with the 2 jumper wires in place. but when i take them out, and replace them with the 2 fp relays, the fuel pumps do not turn on. there is a wire running from the relay terminl number 85 to the ecm. the manual told me to get an ohm reading from the terinal to to ecm pin number j1-23 which did register a positive number, which is to eliminate the possibility that the ecm is bad. it appears to be ok, but i noticed in the blowup of the ecm diagram that j1-23 is supposed to be blank which has me concerned.

 

[JustJason]

Re: 1998 cobalt 7.4 volvo fuel injected

put the relays back in. Have somebody at the helm turn the key while you hold your finger on the relay.
do you feel a click?

 

[Bondo]

Re: 1998 cobalt 7.4 volvo fuel injected

but the reason i am getting no fuel pressure is because for some reason the fuel pumps are not coming on unless i use a jumper wire where the 2 fuel pressure relays go.

Ayuh,...
I don't do Volvos, nor 'puter driven EFIs....
But,...
I'm pretty Sure the fuel pumps only Run(aka. have Power) when the motor is either being started, or when Running....
In other words,...
I Don't believe you should see the pumps running with Just the key in the "On" position...

The fact that it runs, At All,.. tells Me they OK....

 

[45Auto]

Re: 1998 cobalt 7.4 volvo fuel injected

From Granger65's original post:

it idles and revs fine out of the water

From Granger65's post #3:

it had been running great but the water pump went out and it started running hot so we had a new pump put on it.

From Granger65's post #6:

We Went Ahead And Had The Heads Redone And Also New Headgaskets Just To Make Sure After It Ran Hot, But It Only Ran Hot For A Moment Or So

So you had the heads redone? Then it quit running? And the fuel filter is full of orange, rusty water?

Well, does it run out of the water or not?????

It's very confusing and hard to tell from your later posts. When it runs out of the water, it's under essentially no load. Which means it will need very little fuel to run. When you put it in the water, it requires more fuel flow to deliver the required power to turn the prop in the water. Sounds like you definitely have a fuel flow problem. Get it running out of the water and measure the fuel pressure. It's most likely very low. Then find out where the pressure loss is.

If it's low right out of the tank, you possibly have a clogged pickup or filter in the tank.

From the tone of your posts, the best, quickest, and cheapest thing you could do is take it to a shop and let someone who knows what they are doing fix it!

 

[Don S]

Re: 1998 cobalt 7.4 volvo fuel injected

so now i'm concerned that the seloc manual is misprinted or incorrect.

Do you have the engine serial number, or maybe the FULL engine model number handy?
I might just find some information that might be correct.

 

[GRANGER65]

Re: 1998 cobalt 7.4 volvo fuel injected

The Engine Id Number Is Faded Really Bad On The Silver Decal. I Got The Number Off Of The Ecm And It Is 74l0pfi/98ceo1

To Ansewer The Other Question And Clarify This Post. It Would Crank And Run Last Summer But Would Not Go Down The Lake, It Would Just Stumble And Go Dead And Not Even Pull Away From Dock. So We Let It Sit All Winter And When We Got It Out And I Found This Forum, I Originally Posted About What It Was Doing Last Summer Then When I Started To Follow Everyones Ideas On The Board, I Found Out That Now It Would Not Even Crank At All. I Diagnosed The Problem As No Fuel. I Also Found Out That The Relays Are Not "clicking" When The Ignition Is Turned On And The Only Way To Get The Fuel Pumps Working Is To Hot Wire The Relay I Hope This Clarifys The Post