I could use some help. I have been trying to find the problem with my 1989 Formula 350. The car has the original engine but the gentleman I bought it from did some head work after it blew a head gasket. Not sure if the head work is related or not. The air pump has been disconnected and plugged off.

So the problem is that the car idles rough and seems to be searching for the correct idle speed. It also has no low end power (will hesitate when you hit the gas and will not spin the tires on pavement). Once you get up over approximately 3000rpm the car runs fine. It is not blowing any smoke, does not leak anything and it doesn’t seem to matter if the car is warm or cold. Happens all the time. No dash codes.

So, what I’ve done so far..
Replaced the TPS, MAF, new plugs, wires, distributor cap, rotor, and wires. Plugs all looked good but #1 was a little darker than the rest. A temp gun on all the cylinders gives me a similar reading except the front two which are slightly cooler - guessing due to the fan being up front.

It’s driveable and runs good otherwise. It can be a little hard to start at times but it does always start and it doesn’t die, even at idle.

Thinking injectors are next but before I tear it all apart, any other thoughts?

Appreciate the help.

Thanks - Mike

 

Have you adjusted the valves ?
Sounds like a lean surge if it’s not the valve lash sounds like your down to injectors not flowing correctly.

 

Didn’t think about valves. Ill give it a shot. Thanks!

 

Is the timing set correctly?

 

Timing is set at 6 deg.


Thanks.

 

sounds like a timing issue for sure. I recommend advancing the distributor and drive it and listen for knocks, then back it off until the knocking stops. Reason is , the balancers slip a lot on these cars and your timing might still be way off! If you had a bad injector the car would almost always stall out at a stop. You can ohm test them if you want though. Find TDC on the motor by putting a thick piece of wire in number spark plug hole and make sure the rotor is pointing diagnal towards the number one spark plug ,then check the balancer and make sure its correct. ALso, look at the timing chart i posted. Most people get 6 degrees wrong.

 

Check the usual things first. Timing, fuel pressure. Fuel pressure is checked with a gauge hooked up to the rail, the car idling, the vacuum hose disconnected from the regulator and plugged off. Look for 43.5-45 psi. Timing is checked with the EST wire unplugged.

 

Thanks!


I have checked the fuel pressure - right at 43 (a little on the low side but I think it's still good?) but I didn't pull the regulator line. Hadn't considered the balancer may be off. The injectors did check good when I did the ohm test but I wondered if one or more is leaky - these are the originals and the car has 125,000 miles.


Dumb question but what/where is the EST wire? I should probably know I guess...

 

The est connector might be here or next to the strut tower. It is a tan with black stripe wire. Timing is 6 degrees btdc. Even though the injectors ohm out ok the multecs are problematic.

 

Got it. Thanks!