89 6cyl Gas Problem

[cksamartin]

Wife's 89 mustang is having some kind if weird problem where it won't start. The car sat unused for almost a year. Turns over, has good compression, but won't start. Wouldn't even run with starter fluid sprayed into it.

Called in my father inlaw mechanic (retired big truck mechanic). He's baffled. Has tried:

Changing fuel filter
Checked the timing
Checked the distributor cao and plugs/wires
Checked the fuel pump

The pump cycles for a few seconds then stops- i remember it always doing that- a very audible brief run, which i assumed was building pressure in the line. It has been changed, less than 20,000 miles ago.

He has wired the pump to direct current and confirms it will run longer.

Question: is it supposed to run longer than a few seconds?

He has since been able to get the car to run briefly with the tank off, direct feeding fuel into the lines.

Anyone have any ideas on this? Could there be some kind if valve ir sensor that's gone bad preventing fuel from making it from the tank to the engine?

 

[Shawneebear93]

I'm assuming it is actually a 4 cylinder and the title is a typo.
There is a relay for the fuel pump under the driver's seat, it's possible that could be bad (common issue among Fox Mustangs) but if you said it wouldn't even start with starter fluid I'm not sure if this is your problem.
Also if it's been sitting it might not be a bad idea to clean both battery cable ends and terminals as well as the grounds in the engine bay.

 

[cksamartin]

Whoops, yeah, 6cyl.

Changed the relay... Still not working. Between battery and relay, working from relay toward battery, what would be the next most likely failure? It sure seems like the car just isn't telling the pump to run- the pump itself is good.

 

[KhanTyranitar]

If it won't run on starter fluid then either you have no compression (unlikely), or you are not getting spark. You gotta go to the basics and figure out what is missing. Spark, fuel, and compression. One is missing, you find out which and your problem will be solved.

A yellow spark is the same as no spark, you need a bright blue well defined spark.

 

[cksamartin]

If it won't run on starter fluid then either you have no compression (unlikely), or you are not getting spark. You gotta go to the basics and figure out what is missing. Spark, fuel, and compression. One is missing, you find out which and your problem will be solved.

A yellow spark is the same as no spark, you need a bright blue well defined spark.

Plugs were the first thing my father in law changed. I haven't seen it, but he assures me it has good spark (he's retired and has lots of tinkering time in the day, so he's been doing most of the work)