Not a GM but really frustrating.

[grouch]

I have an older pickup that I bought to help a guy out. It was winter and his power was about to be cut off. So, I'm now the proud owner (NOT!) of a 1990 Ford F-150 with a later engine. It had a lot of issues but I've fixed all the mechanical stuff it needed and then some.

I can NOT get the silly thing to fire. It's holding proper fuel pressure. New plugs and plug wires. New injectors. Nobody can test the computer so even that has been replaced. It will not hit a lick on either starting fluid or brake cleaner. I get a timing light signal when cranking. I don't have a noid light but a test light on an injector does flash. I asked an auto electric place what they thought might be the issue. Something is keeping the code reader from reading anything and the CEL (check engine light) doesn't light up.

It was running. It just kept getting worse and worse and now won't run at all. Any ideas are welcome. It did have a partially plugged exhaust so the exhaust stops where the converter used to be.

 

[justchecking]

Crank position sensor (if it has one)? My daughters Jeep would randomly quit with no codes. I replaced the CPS and that fixed it.

 

[gooffeyguy]

1990 is OBD1 and not Obd2, so the codes are read by either jumping the connector in the engine bay or hooking up a reader that has an LED light and count the flashes (or flashes of the check engine light if jumping the connector). The vehicle may have an obd2 plug under the dash, but it's not connected to anything. My 95 mustang does, but I have to use the connector in the engine compartment. On an F150 it's located on drivers side up near the firewall in the corner

No crank position sensor on it either.

Could be Mass Air Sensor. Most ford's switched from speed density to mass air right around 1989/90

Could be bad modual on the distributor. Some years have the modual not on the side of the distributor but mounted remotely not too far away.

EGR valve on the intake just behind the throttle body could be bad, but usually it will start but just not want to idle if that's sticking. They get carbon fowled and can usually be removed and cleaned with carb cleaner.

 

[grouch]

After the rain let up, I went back out to trouble shoot it a bit more. It looks like the computer isn't getting power. There are three almost identical relays that are color coded. I suspect one is the culprit.

I had the proper code reader. I had to hunt as it hadn't been used in 15-20 years. This has turned into a personal affront. Now I remember why I don't normally fool with Fords of this era. Newer and older, yes. OBD I, no. I posted this problem over at a Ford site and got some really snotty little children informing me it ISN'T OBD I. Whatever.

It was a decent running truck. I bought it to help a guy out and it's eating my lunch.

 

[drakon543]

so id have to be there to help further past your potential computer problem but ill try to help you with a few bits of information. you said later engine?? do you know what year the engine came out of? they flipped firing orders like mid model run once. also if its an old ford dont bother trying to run some super fancy plug get cheap autolites and nothing else. check your ignition switch ford has never made a good ignition switch and double check the wires too and from. and lastly if its missing the plug wire separators go buy some and keep the wires seperated and save yourself some more headaches.

 

[exp500]

The firing order is different on a 94, so that means the injectors too. Swap Injector leads and plug wires. Unless you want to swap all the wiring and computer too. Should run unless CPS ring is different number of slots. Good Luck and keep updating us.

 

[exp500]

These Links might help -
Part 1 -Ford 4.9L, 5.0L, 5.8L Index of Articles

 

[grouch]

The link looks promising and I'll check it out if I can't find the issue soon.

As for what year engine, I don't know for sure. It's a '94 or later because of the firing order. I thought it was wired wrong. I wired it right for the year and it wouldn't run. Wired it back like the '94 firing order and it fired right up. As for the injectors,the pre-OBD II injectors are not sequential. They alternate from side to side. One entire back fires. It took a bit to find that out. The Ford dealer wasn't any help.

I had an epiphany reading the responses. I was thinking ignition switch if the relays were all good. Then I realized it's a wear item and the start is by a button under the dash. When the rain lets up (I've dumped over 5 inches out of my gauge over the last three days) I'll pop the switch out.

I'll say one thing, the folks here are more help than the F-150 site.

 

[iamdub]

LS swap.

 

[grouch]

LS swap.

I can find better uses for an LS if I came on one.

Pulled the ignition switch out today. It fell apart in my hands. Slapped a new one in there, no joy. I'd part this thing out, but I'm taking it personally.