Cold Start / hot start

[scotstern]

I have a cold and a hot start problem. The car has 13,000 total miles on it and I have owned it for more than 20 years. It was difficult to start but once it warmed up it ran great. It had a hot start problem after it was warm but the O rings looked good and it has a relatively new accumulator, fuel pump and check valve installed. The resting pressure was about 1 minutes worth.

I took out the WUR, which was definitely defective, the CSV, the FV, the pressure regulator and the injectors and sent them to John Harvey. He cleaned and reconditioned the CSV, the FV and the injectors. He sent me a new WRU, accumulator and fuel filter. I installed everything except for the accumulator and filter as my plan was to drive the car to a local place that has a lift and have them do that job.

The car was and is, next to impossible to start now. If I can get it started, which I seem to be able to do by playing with it a bit, it will only idle (rough) and it is almost impossible to get it to allow more than idle speed without cutting out. It seems to backfire if you try to increase throttle at all. Occasionally, you can nature it up to normal rpm's but it is difficult at best to do even that. Even after it is totally warm, it still is difficult to get the rpm's up and it still backfires.

I do not seem to hear the frequency valve or feel it vibrating but the connection is good and my hearing might be a bit off. The idle speed valve does seem to hum and I can feel it vibrate. I can not find any vacuum leaks so I think that is not the issue. I have not touched the mixture, which might have been set to compensate for the WUR that did not work, by DMC. I am not sure but I am reluctant to touch that until everything else has been eliminated as that appears to be a slippery slope.

Any thoughts as I live over 100 miles from DMC (I'm in San Diego) and I would like to get it running enough to at least get it there if that is necessary. This is really disappointing as it is actually worse now than before I started.

Scot Stern
6452

[sdg3205]

Hey scot.

Are you 110% sure the fuel lines were reinstalled correctly? It can be very easy to route a hose or two the wrong way. Often the car will run, but poorly.

There is a fuel hose routing diagram available here.

[scotstern]

Hey scot.

Are you 110% sure the fuel lines were reinstalled correctly? It can be very easy to route a hose or two the wrong way. Often the car will run, but poorly.

There is a fuel hose routing diagram available here.


Actually, that is what it sounds like but I did not remove the lines from the distributor in order to change the injectors. I took them off at the injector side and they would be hard to mix up because of the length. On another note, I did try jumping 12 volts directly to the FV and I do get a small spark but no vibration or hum. I only touched it as I know that the duty cycle is not full time and I did not wish to damage it.

[Bitsyncmaster]

I bet your mixture is not adjusted as it should be. That would cause the FV not to buzz. But make sure your connector on the vacuum advance solenoid did not fall off. That would cause some warm up problems.

[sdg3205]

Actually, that is what it sounds like but I did not remove the lines from the distributor in order to change the injectors. I took them off at the injector side and they would be hard to mix up because of the length. On another note, I did try jumping 12 volts directly to the FV and I do get a small spark but no vibration or hum. I only touched it as I know that the duty cycle is not full time and I did not wish to damage it.

Actually the injectors don't matter since its CIS. I'm more talking about the lines to the WUR, FV, CSV etc

[scotstern]

Actually the injectors don't matter since its CIS. I'm more talking about the lines to the WUR, FV, CSV etc

Never took the wur or csv lines off of the distributor. The only line I had to take off was the FV line as I needed to send the whole thing to John. That was the only one and it went back on in the exact same spot. Now, the car starts fine as long as I stay off of the gas. As soon as I try to step on the gas it starts to backfire and cuts out.

[scotstern]

OK, I can't believe it but bitsyncmaster was correct. First I tried to remove the connector on the oxegen sensor but I could not get to it soI tried to lean it out a bit and it got progressively worse! At as much as a quarter of a turn the backfires were noticeably worse. I then went back to were I was and then thought "what the hell" and went a little bit richer and all of the sudden everything settled down and it was running better. Went even a bit more, to the rich side, (clockwise) and it really made a positive difference. The car seems to run alright now and is drivable. I still have the hot start issue but that will probably turn out to be the accumulator.

Thanks for you assistance bitsyncmaster you were correct. On another subject, where is the vacuum advance solenoid located? I would like to check it to be certain that I did not knock off anything.

Thanks so much,

Scot

[Bitsyncmaster]

Vacuum solenoid is behind engine about in the center. That connector falls off very easily.

You really need to get a dwell meter to set the mixture correctly.

[scotstern]

Vacuum solenoid is behind engine about in the center. That connector falls off very easily.

You really need to get a dwell meter to set the mixture correctly.

Thanks, I have a dwell meter that I use for my MGB as it has points. How do you use it to set the mixture?

[Bitsyncmaster]

Thanks, I have a dwell meter that I use for my MGB as it has points. How do you use it to set the mixture?

I connect it to the orange wire on the two pin connector that connects to the diagnostic port. But it should work connecting to the FV directly. You set your meter tor 4 cylinder. You adjust the mixture after your engine has thoroughly warmed up. I think your looking for about 30 degrees but it will be swinging up and down so just get it close to that value.

You test your meter by pressing the wide open throttle switch. The meter should hold a solid 48 degrees.

[scotstern]

I connect it to the orange wire on the two pin connector that connects to the diagnostic port. But it should work connecting to the FV directly. You set your meter tor 4 cylinder. You adjust the mixture after your engine has thoroughly warmed up. I think your looking for about 30 degrees but it will be swinging up and down so just get it close to that value.

You test your meter by pressing the wide open throttle switch. The meter should hold a solid 48 degrees.

Did exactly that and the meter registered 55 degrees on the 4 cylinder setting and did not move much. When I tried to adjust the mixture the meter stayed the same unless I pushed too hard on the allen wrench making the throttle plate open a bit and then it went down to 30 degrees or so. as soon as I released the pressure on the wrench it went back up to 55 degrees.

Should I try reversing the leads? Right now I have the black to ground and the positive to the orange wire on the unused connector at center of the rear of the engine. I have the selector set on dwell and it seems to read 55 or so constantly.

[David T]

You should see the meter bouncing, that way you know it is in closed loop. If it is not you may not have the O2 sensor hooked up or it may be fouled or contaminated. You cannot adjust the mixture with the dwell meter unless it is running closed loop (ie, reading the O2 sensor). If the frequency valve is not buzzing you cannot adjust the mixture properly either.
David Teitelbaum

[Bitsyncmaster]

Did exactly that and the meter registered 55 degrees on the 4 cylinder setting and did not move much. When I tried to adjust the mixture the meter stayed the same unless I pushed too hard on the allen wrench making the throttle plate open a bit and then it went down to 30 degrees or so. as soon as I released the pressure on the wrench it went back up to 55 degrees.

Should I try reversing the leads? Right now I have the black to ground and the positive to the orange wire on the unused connector at center of the rear of the engine. I have the selector set on dwell and it seems to read 55 or so constantly.

My mistake. You get 54 degrees when the wide open throttle switch is on. I'm sure that is your problem or your lambda ECU is bad. Unplug the WOT switch and see if it works better. The cold temp switch also shares that wire of the WOT switch so if it's shorted that could also cause your problem.

I use a meter which reads in duty cycle. I was doing the 60% reading conversion in my head.

[Ron]

Should I try reversing the leads? Right now I have the black to ground and the positive to the orange wire on the unused connector at center of the rear of the engine. I have the selector set on dwell and it seems to read 55 or so constantly.
You have the leads correct. Your target is 40° (+/- 5° pulse).
I agree with Dave that the WOT circuit may be grounded, see E below. Go through the rest of the list if not for more clues....

5. Pulse Ratios:
A. Normal Operation (Sensor connected and CO properly adjusted) — 35-45° (reading pulsates)
B. Oxygen sensor disconnected — 40-50° (steady reading)
C. Oxygen sensor lead disconnected. Ground lead — 87° minimum (steady reading)
D. Oxygen sensor lead disconnected. 1.5 volts applied to lead — 20° maximum (steady reading)
E. Full throttle or engine cold (below 15°C or 59°F) — 50-60° (steady reading)

Make sure you plug the CO adjustment access hole and give it a few seconds to settle down when reading...