Getting around 11 MPG, running rich, need help

[Z Tyler Z]

Zed Head

Edit - I agree on FP measurements. A little disappointed that Z Tyler Z didn't measure before replacing parts but good luck to him.

No worries I didn't go and buy one I had one laying around from a trade and decided to see if it'd work. When I get some time I'll take Z trains advice and go and get a Fp guage.

On the way home today I was still getting that gutlessness with my car. I can still put the pedal to the floor in first and only slowly gain speed. I still think the Air to fuel is off but haven't a clue where to look now.

Well see how tomorrows trip goes mpg wise.

[jthill3]

I was getting about 18 also before I put an aftermarket regulator on. Now I get a consistent 20 (at least 6 fill-ups calculated since I put it on). I have a 76.

jthill3 - Just for my own personal interest, what fuel pump and regulator are you using? I'm still wondering about these high rate, high pressure pumps that the auto stores sell as replacement pumps for the Z cars.

Edit - I agree on FP measurements. A little disappointed that Z Tyler Z didn't measure before replacing parts but good luck to him.

Well these were not replaced as they are still the ones that were on the car when I bought it two years ago. Any suggestions?

I am also getting slow response in 2nd gear as the accerlation gradually increases.

[Z Tyler Z]

Ok now I'm getting around 15 mpg with a mix of city and highway driving.

New problem I'm starting to notice is that the car doesn't like to be driven when cold. It tends to be gutless and idle very low (500-600). Any ideas? The problem is gone when I turn the car off and back on. When it idles low the BCCD doesn't turn on and hold the idle, it just drops right to around 600 when I putt he clutch in.

[jthill3]

Ok now I'm getting around 15 mpg with a mix of city and highway driving.

New problem I'm starting to notice is that the car doesn't like to be driven when cold. It tends to be gutless and idle very low (500-600). Any ideas? The problem is gone when I turn the car off and back on. When it idles low the BCCD doesn't turn on and hold the idle, it just drops right to around 600 when I putt he clutch in.

Hey Z Tyler - Mine ran at 11 MPG for the longest and we found that the Thermotine Switch had been wired backwards by the prev owner. It was corrected and I am up to 18 MPG now. Next for me, I will replace the Fulle Pressure Regualtor....

[Z Tyler Z]

If I remember correctly the thermotime switch controls the Auxiliary Air Regulator right? I wonder if I just removed that if it would solve my problem. I was planning on removing it eventually to make room for a strut bar anyway S30driver drives without his up here without any problems. He says he just has to manual warm it up (rev it for a while) before driving.

[Zs-ondabrain]

Ready to Put a set of SU's on there yet? Tyler? Ready when you are. Just pick up a set and I'll help instal them and gladly RIP all that Fuel Injection crap out. Hell, I'll even let ya put it in MY garbage can, this time. LOL

Dave

[S30Driver]

The thermotime switch tells the cold start valve when to operate & enrich the fuel mixture or prevent it from injecting fuel depending on temperature.

Your cold running drivability problems might be a problem with the wiring harness between the engine bay & ecu. Check those connections just after the wiring that leaves the thermostat housing. I think they are bullet connectors.

And, try to resist the siren call of the su's for now....

[Zed Head]

Ok now I'm getting around 15 mpg with a mix of city and highway driving.

New problem I'm starting to notice is that the car doesn't like to be driven when cold. It tends to be gutless and idle very low (500-600). Any ideas? The problem is gone when I turn the car off and back on. When it idles low the BCCD doesn't turn on and hold the idle, it just drops right to around 600 when I putt he clutch in.

The BCDD is not designed to "hold the idle" at low RPM. It is designed to maintain a certain pressure in the intake manifold at high RPM, throttle closed operation. I have read that they can get stuck but giving a high idle, not a low one.

And the AAR is on its own circuit, designed to hold the idle up for a short while after starting. You could take it off and test it or disconnect the hose and block both ends to see if it has an effect.

The BCDD is described in the Emissions section of the FSM and the AAR in the Engine Fuel section.

15 mpg is still pretty bad. How's the fuel pressure?

Don't forget to get a new low pressure fuel pump or low pressure regulator if you go carbs. Otherwise, you'll really be running rich.

[olzed]

Hell. You guys must be sick of all the crap with stuffed 35 year old injection systems.

Let Dave drop on a set of SUs Tyler, and your car will fly.

[Zed Head]

Dave, you seem like a very helpful, knowledgeable guy. But I have to say that it is ironic that the "Electrical Hero Wanna Be" says to ditch the electronics and go back to mechanical.

I'm just sayin'. It's funny.

[Gary in NJ]

Bosch L-Jetronic fuel injection is an "unintelligent" analog system. I'd much rather have the SU's. They are simple and EASY to understand.

[Zs-ondabrain]

The partial phrase of "Wanna Be" implies that I'd like to be smart enough to just go out and fix his FI system, without having to "Go back to school" to do it. I like the Z's for their simplicity, not for their Simply Old FI parts.

Occasionally, Mechanical is better than electrical. This is one of those times. And yes, I do see the Humor in it. And I'll be giggling when his SU powered Z is screaming down the road getting 25MPG.

Dave