Help my car is messed up top speed of 45 mph!

[MatthewCervi]

Yes, the pressure valve is the screw-in fitting on the back of the pump.

One way to tell if it is working more-or-less correctly is to turn the ignition to the "on" position (not starting the engine) so that the fuel pump comes on. The sound made by the pump should rise as it builds to 30 psi then change abruptly when the pressure valve opens. Then a second later you should hear the gas in the return line hit the gas tank (more noticeable if the tank is emptier).

My votes for the problem:

- cold-start valve on all the time or leaking (feel the tip for dripping a couple minutes after the car has started)

- throttle position not synchronized to injection pump (or linkage binding). See the download documents others have referenced for how to do this correctly.

- warm-up regulator not adjusted correctly.

- badly clogged air filters

I doubt it is the injectors. First, having all four of them be defective seems unlikely. Second, the injection pump is only going to meter out so much fuel; if the injectors were weak you'd just get bad atomization, not excess fuel.

[c.d.iesel]

COMPRESSION TEST

VALVE ADJUSTMENT

DWELL & TIMING WITH METER AND STROBE LIGHT

28-30 PSI FUEL PRESSURE

NEW FUEL FILTER

CORRECTLY ADJUSTED/FUNCTIONING WARM-UP

REGULATOR CHOKE

CORRECTLY ADJUSTED THROTTLE LINKAGE

IN THAT ORDER............

[Durango_Dave]

I always forget about the cold start injector cos mine is only turned on by a switch !

But none of those rich running problems easily account for the 45mph limit.. thats kind of strange.

anyway, like everyone says check all that stuff and report back!

They're talking about the warm-up regulator on the mechanical fuel injector pump, not the cold start injector. Around here, I had to back off the warm up regulator to compensate for the high elevation. If yours is stuck in the cold position, the mixture will never get leaned out as the engine warms up. Very easy visual check, and it doesn't hurt to douse this part with some silicon spray ever once in a while.

[_z_]

They're talking about the warm-up regulator on the mechanical fuel injector pump, not the cold start injector. Around here, I had to back off the warm up regulator to compensate for the high elevation. If yours is stuck in the cold position, the mixture will never get leaned out as the engine warms up. Very easy visual check, and it doesn't hurt to douse this part with some silicon spray ever once in a while.

well Along with a stuck warm up transmitter (or regulator -- i've seen it both ways) a known rich running problem is that the thermo-time switch or some other part of the system that controls the cold start injector gets stuck 'on' (like a short or some strange voltage going to the injector)-- so the injector keeps squirting fuel beyond the usual second or three during starting when the engine is totally cold.

When diagnosing tii rich running I forget about that because I put a switch interrupt in my system, so I kind of forget about the possibility that it could be stuck on.

So along with the other reasons for rich running, we gotta remember the old cold start injector being on all the time possibility!!

[Guest]

I had similar symptoms some time back. Turned out to be the fuel filter.

Good Luck!

Nate Campbell

San Antonio, TX

'73tii

[Guest]

I had similar symptoms some time back. Turned out to be the fuel filter.

Good Luck!

Nate Campbell

San Antonio, TX

'73tii