Engine Stalls Under Acceleration, '72 1.7L FI / Anyone in the area to help? Options

[1adam12]

Okay, I think I'm done on this one and throwing in the towel. I've been going through the vacuum lines for over three months. I know that seems long but finding an accurate 1.7L FI California carb diagram has been like trying to find the Holy Grail. I had help from Jeff B. and put the best two diagrams together in an effort to clean things up in my engine bay.

I purchased my '72 1.7L back in April and when I first started it there was rough idle as expected but it revved. Once I started replacing the old vacuum lines I must have reversed some lines because that's when the problem started.

The car starts right up and has good idle around 2500 then drops just above 1K so I believe the cold start and AAR are working fine. When I manually open up the throttle, the engine bogs, and the rpm's drop. It's as if there engine is starving for air and doing the exact opposite when throttle is opened.

I went ahead and purchased and installed 914rubbers 1.7L TPS board and there was absolutely no change. I also rerouted some of my vacuum lines again to where I believe they are spot on.

Could the problem be my MPS or possibly Decel Valve? Anyone near the Chino Hills area this weekend? My goal is to get her off jack stands this weekend! I would love to try someone else's MPS or Decel to help me in my process of elimination. (IMG:style_emoticons/default/headbang.gif)

[1adam12]

Just to add, I also emptied and cleaned the fuel tank and replaced the fuel filter. I have not had the injectors tested or replaced. Just purchased a new battery as well so should be getting sufficient power supply.

[mgphoto]

Okay, I think I'm done on this one and throwing in the towel. I've been going through the vacuum lines for over three months. I know that seems long but finding an accurate 1.7L FI California carb diagram has been like trying to find the Holy Grail. I had help from Jeff B. and put the best two diagrams together in an effort to clean things up in my engine bay.

I purchased my '72 1.7L back in April and when I first started it there was rough idle as expected but it revved. Once I started replacing the old vacuum lines I must have reversed some lines because that's when the problem started.

The car starts right up and has good idle around 2500 then drops just above 1K so I believe the cold start and AAR are working fine. When I manually open up the throttle, the engine bogs, and the rpm's drop. It's as if there engine is starving for air and doing the exact opposite when throttle is opened.

I went ahead and purchased and installed 914rubbers 1.7L TPS board and there was absolutely no change. I also rerouted some of my vacuum lines again to where I believe they are spot on.

Could the problem be my MPS or possibly Decel Valve? Anyone near the Chino Hills area this weekend? My goal is to get her off jack stands this weekend! I would love to try someone else's MPS or Decel to help me in my process of elimination. (IMG:style_emoticons/default/headbang.gif)

Check the trigger points in the base of the distributor, grease and oil can contaminate them, they are low voltage so they never burn it off.


not going to be decel valve.
possibly MPS, check vacuum.

Mike

[1adam12]

Here are the two images of vacuum lines that I've mirrored which are closest to my set up. First one taken from Pelican site and other from Jacksun who's a member here. The only difference between the two is where they routed the small hose from the decel valve. One image shows going to manifold branch piece and the other version shows going to the AAR branch which I just ordered from 914rubber.

I've also read somewhere that it was suggested that both of the larger hoses from the decel valve should be connected to the manifold which I originally tried but I currently have the side port hose now running to 'T' connection which connects to the intake hose.

[1adam12]

Thank you MGphoto for the fast response! This engine bay was very dirty and oily. I've misunderstood where the trigger points were. I'll check that out now and make sure they're cleaned. Will double check that MPS has vacuum.

[76-914]

Why were you looking for a carb diagram if your running DJet? Disconnect all vacuum lines except the MPS. Plug any vacuum openings then start the car. If that did begin adding one component at a time back into the system until you find the culprit. If that didn't do it I'd check timing and the advance plates inside the dizzy. (IMG:style_emoticons/default/beerchug.gif)

[BeatNavy]

Hey, I recognize that picture in the hose routing picture with the labels. I think that's mine from several years ago when I had my 1.7L (IMG:style_emoticons/default/smile.gif)

I generally agree with the other suggestions. I think if you're starting up ok and idling fine then your hose routing is probably ok. Based on your description, I'd focus on either timing (probably retarded) or fuel delivery. (I agree it's not the decal valve.)

I would:

1. Verify dwell and timing

2. Verify fuel pressure

3. Check MPS holds a vacuum (is it stock or has it been opened up and "repaired"?)

4. Go ahead and get the injectors serviced. If you can spare 5 days and about $80 (or whatever it is), Mr. Injector will square you away. VERY helpful for eliminating variables on fuel delivery.

5. Inspect, clean, and re-grease dizzy and trigger points.

[mgphoto]

Why were you looking for a carb diagram if your running DJet? Disconnect all vacuum lines except the MPS. Plug any vacuum openings then start the car. If that did begin adding one component at a time back into the system until you find the culprit. If that didn't do it I'd check timing and the advance plates inside the dizzy. (IMG:style_emoticons/default/beerchug.gif)

California Air Resources Board, control air quality.

[mgphoto]

Here are the two images of vacuum lines that I've mirrored which are closest to my set up. First one taken from Pelican site and other from Jacksun who's a member here. The only difference between the two is where they routed the small hose from the decel valve. One image shows going to manifold branch piece and the other version shows going to the AAR branch which I just ordered from 914rubber.

I've also read somewhere that it was suggested that both of the larger hoses from the decel valve should be connected to the manifold which I originally tried but I currently have the side port hose now running to 'T' connection which connects to the intake hose.

Your plumbing looks to be correct, I have not seen a 1.7 with both vacuum advance and retard, could be the California thing.

I believe the vacuum nipple before the butterfly is advance, port on the vacuum can closest to the dizzy body, retard, behind the butterfly connects to the port farthest from the dizzy.

You could lose the decel valve. just cap the ports, it doesn't help your engine.

[mgphoto]

Also check the fuel hoses for kinks, you said you changed the fuel filter.

[1adam12]

I absolutely love this forum! I think I have enough information collected here to continue going in the right direction. I'm very intrigued with the DJet system and I'm determined to get her going.

[iankarr]

Also check the fuel hoses for kinks, you said you changed the fuel filter.

(IMG:style_emoticons/default/agree.gif)
Sounds a lot like fuel starvation. You mentioned you cleaned the gas tank. It's possible (probable) when you replaced the tank, the hose(s) became kinked underneath. That's exactly the way my car behaved after I serviced my tank. Remove the skid plate under the car and inspect the hoses through the hole.

[Ed_Turbo]

I am not sure if I can make it this weekend but I would love to lend an extra hand in the future. Not familiar with D-Jet only L-Jet. Let me know bud.

[1adam12]

I am not sure if I can make it this weekend but I would love to lend an extra hand in the future. Not familiar with D-Jet only L-Jet. Let me know bud.

Thanks Ed. Much appreciated! Hopefully I can resolve as much as I can this weekend but I'll keep you in mind and always good to meet local So Cal members.

[mgphoto]

Also check the fuel hoses for kinks, you said you changed the fuel filter.

(IMG:style_emoticons/default/agree.gif)
Sounds a lot like fuel starvation. You mentioned you cleaned the gas tank. It's possible (probable) when you replaced the tank, the hose(s) became kinked underneath. That's exactly the way my car behaved after I serviced my tank. Remove the skid plate under the car and inspect the hoses through the hole.

This is a possibility but the engine is freewheeling, not under load when bogging down, (am I correct ?).
There should be enough fuel in the ring to rev the motor, something that immediate might be a fuel pump problem. Pump can't supply enough fuel to rev the motor, easy check with a good pressure gauge.

[euro911]

I'd start by adjusting the valves. If they're not right, everything else will be 'off'. I had a similar problem with my wife's 1.7L and I was chasing my tail for a long time. I finally bit the bullet and adjusted the valves (found two intake valves that were too tight) and the car ran great.

[1adam12]

The first thing I had time to check just recently was the fuel lines. Like Mgphoto suggested, there was a bad kink on the larger hose under the fuel tank. I had to cut the length back about 2 inches so there wasn't too much slack on the line when placing the fuel tank back down. Unfortunately, this didn't change the loss of power but it's good that I fixed that. Next up: MPS vaccuum, Fuel pump, Distributor trigger points, then valve adjustment.

[914_teener]

The first thing I had time to check just recently was the fuel lines. Like Mgphoto suggested, there was a bad kink on the larger hose under the fuel tank. I had to cut the length back about 2 inches so there wasn't too much slack on the line when placing the fuel tank back down. Unfortunately, this didn't change the loss of power but it's good that I fixed that. Next up: MPS vaccuum, Fuel pump, Distributor trigger points, then valve adjustment.

My .02.

The first thing I did with my 1.7 was go down to HF and get a cheap vacuum gauge and test the MPS to hold vacuum.

If that is not working correctly with D-jet, it will never be right.

I'd do that.

[poorsche914]

Check the FI harness grounds. Seems like that was the culprit on a 2.0 D-jet I had years ago. I never did solve the issue and sold the car cheap. New owner figured it out (IMG:style_emoticons/default/dry.gif)

(IMG:style_emoticons/default/driving.gif)

[euro911]

Do one item at a time, so you know exactly what fixes the problem.