1.7 dies right after starting Options

[averagejoe71]

my 1.7 dies when it starts. Ill turn the key and it will shortly after stop and if i touch the pedal alittle within the small time frame it dies. Does anyone have any ideas of where to start checking to see whats the problem. All help is appreciated.

[BeatNavy]

Fuel injection or carbs? If FI, first thing I would check is the Cylinder Head Temperature (CHT) sensor. If it's disconnected or not functioning, the ECU will basically dump fuel into the engine and flood it. You may be able too smell fuel. Also, check the MPS to make sure it's hooked up and holding a vacuum. With FI those are the two most important things to check, assuming everything else (fuel delivery, ignition, etc.) are working.

Good reference for how this stuff all works: http://members.rennlist.com/pbanders/djetparts.htm

If carbs, ignore everything I said.

[averagejoe71]

Fuel injection or carbs? If FI, first thing I would check is the Cylinder Head Temperature (CHT) sensor. If it's disconnected or not functioning, the ECU will basically dump fuel into the engine and flood it. You may be able too smell fuel. Also, check the MPS to make sure it's hooked up and holding a vacuum. With FI those are the two most important things to check, assuming everything else (fuel delivery, ignition, etc.) are working.

Good reference for how this stuff all works: http://members.rennlist.com/pbanders/djetparts.htm

If carbs, ignore everything I said.

Okay thank you. My question now where is the CHT and how do I check the maps if it holds vacuum.

[Tbrown4x4]

The CHT is near the #3 Intake port. I believe my '73 is a white wire going to it. Not sure of other years.

If you don't have a vacuum pump, you can put a hose on the MPS and suck or blow into it. ( There is no easy way to type that with this crowd. LOL) The diaphragm splits and the FI goes rich.

[averagejoe71]

The CHT is near the #3 Intake port. I believe my '73 is a white wire going to it. Not sure of other years.

If you don't have a vacuum pump, you can put a hose on the MPS and suck or blow into it. ( There is no easy way to type that with this crowd. LOL) The diaphragm splits and the FI goes rich.

Thank you for your help. The CHT looks fine and the wire doesn't look damaged. So I checked the MPS and it wouldn't hold vacuum and I had another one laying around and that one only went up to 8 in. Hg before leaking so I think it's safe to assume they are both bad. What are my options now. Is there anyone on the forum?

[mark04usa]

The MPS may not be the cause of the engine to die after start as you describe, but repairing it makes for a better running car. You can get the repair kit for the MPS from Chris Foley's Tangerine Racing:
http://www.tangerineracing.com/mpsdiaphragm.htm

This kit works great. Be sure to get the tuning tool as well. (IMG:style_emoticons/default/beerchug.gif)

[averagejoe71]

The MPS may not be the cause of the engine to die after start as you describe, but repairing it makes for a better running car. You can get the repair kit for the MPS from Chris Foley's Tangerine Racing:
http://www.tangerineracing.com/mpsdiaphragm.htm

This kit works great. Be sure to get the tuning tool as well. (IMG:style_emoticons/default/beerchug.gif)

Interesting. The reason I came to that conclusion that the first MPS that doesn't hold pressure at all the car would start and immediately die. So then when I put the other one the car lasted longer but still died. Any idea of what else could be the problem? Also thank you for the link.

[BeatNavy]

The MPS may not be the cause of the engine to die after start as you describe, but repairing it makes for a better running car. You can get the repair kit for the MPS from Chris Foley's Tangerine Racing:
http://www.tangerineracing.com/mpsdiaphragm.htm

This kit works great. Be sure to get the tuning tool as well. (IMG:style_emoticons/default/beerchug.gif)

Interesting. The reason I came to that conclusion that the first MPS that doesn't hold pressure at all the car would start and immediately die. So then when I put the other one the car lasted longer but still died. Any idea of what else could be the problem? Also thank you for the link.

I'm confused. Did you test the first MPS at all? Does it hold a vacuum? You need an MPS that is serviceable. If neither one holds a vacuum get the Tangerine kit or find a good one somewhere else. Then you can start troubleshooting other things.

A bad MPS could cause the car to immediately die. So could a bad CHT. So could several other things.

[averagejoe71]

The MPS may not be the cause of the engine to die after start as you describe, but repairing it makes for a better running car. You can get the repair kit for the MPS from Chris Foley's Tangerine Racing:
http://www.tangerineracing.com/mpsdiaphragm.htm

This kit works great. Be sure to get the tuning tool as well. (IMG:style_emoticons/default/beerchug.gif)

Interesting. The reason I came to that conclusion that the first MPS that doesn't hold pressure at all the car would start and immediately die. So then when I put the other one the car lasted longer but still died. Any idea of what else could be the problem? Also thank you for the link.

I'm confused. Did you test the first MPS at all? Does it hold a vacuum? You need an MPS that is serviceable. If neither one holds a vacuum get the Tangerine kit or find a good one somewhere else. Then you can start troubleshooting other things.

A bad MPS could cause the car to immediately die. So could a bad CHT. So could several other things.

I tested both. The one originally on the car (the first one) doesn't hold pressure at all. My spare (the second one) only goes up to 8 in Hg before leaking.

[BeatNavy]

Ok, now I'm clear. Then yes, get the Tangerine kit, or find a serviceable one somewhere. You absolutely need a working MPS.

I've done the Tangerine kit twice - it's a satisfying little project, and if you do it right you'll learn a lot about how the MPS works. Before you do that, though, make sure the issue isn't electrical. It's almost always the diaphragm, but test your MPS as with an ohmmeter as follows:

Primary Coil (terminals 7 and 15): ~90 ohms.
◦Secondary Coil (terminals 8 and 10): ~350 ohms.

If those check out, then the kit will help you.

[BeatNavy]

I should add now is a good time as well to think about what else could be causing issues. You didn't give us any history on the car. Was it running before? Was it sitting for a long time? If it has been sitting for a long time, I would do a complete fuel system servicing: inspect fuel tank, change all the lines, change filter, and send the injectors out for servicing. You also need to verify fuel pressure and timing/ignition.

[averagejoe71]

Ok, now I'm clear. Then yes, get the Tangerine kit, or find a serviceable one somewhere. You absolutely need a working MPS.

I've done the Tangerine kit twice - it's a satisfying little project, and if you do it right you'll learn a lot about how the MPS works. Before you do that, though, make sure the issue isn't electrical. It's almost always the diaphragm, but test your MPS as with an ohmmeter as follows:

Primary Coil (terminals 7 and 15): ~90 ohms.
◦Secondary Coil (terminals 8 and 10): ~350 ohms.

If those check out, then the kit will help you.

Original MPS
Primary coil 95.6 ohms
Secondary coil 350 ohms

Spare MPS
Primary coil 95.5 ohms
Secondary 343 ohms

[averagejoe71]

I should add now is a good time as well to think about what else could be causing issues. You didn't give us any history on the car. Was it running before? Was it sitting for a long time? If it has been sitting for a long time, I would do a complete fuel system servicing: inspect fuel tank, change all the lines, change filter, and send the injectors out for servicing. You also need to verify fuel pressure and timing/ignition.

The car was sitting 5ish years when I found it inside a tomato bush. Since then it's been on the road running. I have done no service except for oil Change, clutch, spark plugs cap rotor, and pertronix. I don't know how to check fuel pressure or timing.

[BeatNavy]

I should add now is a good time as well to think about what else could be causing issues. You didn't give us any history on the car. Was it running before? Was it sitting for a long time? If it has been sitting for a long time, I would do a complete fuel system servicing: inspect fuel tank, change all the lines, change filter, and send the injectors out for servicing. You also need to verify fuel pressure and timing/ignition.

The car was sitting 5ish years when I found it inside a tomato bush. Since then it's been on the road running. I have done no service except for oil Change, clutch, spark plugs cap rotor, and pertronix. I don't know how to check fuel pressure or timing.

A tomato bush? Don't hear that one too often (IMG:style_emoticons/default/smile.gif)

A couple of resources you need:

Haynes Manual
D-Jet Troubleshooting

If you can, send the injectors out to Mr. Injector. Replace the fuel filter. Inspect the lines and replace. Replace the vacuum lines all around.

[averagejoe71]

I should add now is a good time as well to think about what else could be causing issues. You didn't give us any history on the car. Was it running before? Was it sitting for a long time? If it has been sitting for a long time, I would do a complete fuel system servicing: inspect fuel tank, change all the lines, change filter, and send the injectors out for servicing. You also need to verify fuel pressure and timing/ignition.

The car was sitting 5ish years when I found it inside a tomato bush. Since then it's been on the road running. I have done no service except for oil Change, clutch, spark plugs cap rotor, and pertronix. I don't know how to check fuel pressure or timing.

A tomato bush? Don't hear that one too often (IMG:style_emoticons/default/smile.gif)

A couple of resources you need:

Haynes Manual
D-Jet Troubleshooting

If you can, send the injectors out to Mr. Injector. Replace the fuel filter. Inspect the lines and replace. Replace the vacuum lines all around.

Thanks for the info. i just got the repair kit in the mail. Now i only have 2 questions. Should i replace the full load stop and tune it? or just do the diaphragm section. Also where do i buy the screws to hold the housing together again.

[BeatNavy]

You can use your existing full load stop. That's no problem. You'll probably need to tune, because I'm not sure how accurate you can be just trying to get the part load screw in at the right depth just by measurement. Did you get the tuning pieces? Helpful, but not totally necessary, I think.

Ok, do you have a wideband O2 sensor, by any chance? If not, you're going to have to attempt to get the part load stop in as close as possible and then your options include:

1. Tune it by "feel," which is not ideal.
2. Take it to a local service where it can be dyno'ed and tuned.
3. Get an inductance meter and tune it yourself.
4. Send it to someone who will do it for you. Bleyseng may still do it as a service (he may charge small fee).

Even after tuning to spec it's still good to tune it based on your experience, if possible. Again, wideband very helpful here.

The instructions should tell you what size hardware you need to replace the rivets. Chris always provides great instructions with his products. If they are not in there for some reason, I'll chase down the leftover packages I have and see what I used.

[averagejoe71]

Sorry for the late update but I only replaced the diaphragm and when I connected back to the car I put the plug in flipped over meaning the 7 pin was connect to the 15 connecter. So I proceed to start the car and it would only crank. So then I reconnected it correctly and it only still crank. After that I went to the relay board and switched the fuel relay with the rear defogger relay and it started and immediately died. So then I switch the power supply with the fuel pump relay and the car started again but shortly after died. Now when I turn the key the car won't even crank. Being the young idiot I am I assumed there is a short on the relay board since I saw corrosion on the pins so I'm currently removing the black stuff from the back of the relay to see if my theory is right. I'm feeling that I should just ripped all this old fi stuff and buy a newer fi system and just throw it on there. Any thoughts or idea for my certain situation. This is killing me.

[BeatNavy]

Likely more than one thing going on, which is not surprising. As far as I know, you still haven't tested the CHT and CHT wiring closely. That could also cause this issue. Or it could be complete fuel starvation, too.

Was the MPS diaphragm ruptured when you cracked open the housing? If it's a matter of getting the repaired MPS in spec I can help tune it. I also have a generally serviceable (I believe) 049 MPS which should work for testing purposes. PM me if want help. In the meantime, I'd recommend at least two checks:

1. Thoroughly checking CHT, the connection, and the wiring all the way to the ECU.

2. Checking to see if fuel injectors are actually getting fuel and firing - pull one out and put it in baby food jar (or something similar) and crank the engine. Is there fuel?

I like my D-Jet, but I've replaced everything on it over the last couple of years in an attempt to get it working well. That includes fuel pump, ECU, MPS, wiring harness, CHT, T1, fuel pressure regulator, throttle body, TPS board, all hoses, etc. etc. Unless you're pretty well versed in modern FI systems, you're also going to have challenges. See the threads currently here on the board about Microsquirt conversions. It requires some knowledge, creativity, and patience to get that working on our cars.

Hang in there.

[averagejoe71]

Likely more than one thing going on, which is not surprising. As far as I know, you still haven't tested the CHT and CHT wiring closely. That could also cause this issue. Or it could be complete fuel starvation, too.

Was the MPS diaphragm ruptured when you cracked open the housing? If it's a matter of getting the repaired MPS in spec I can help tune it. I also have a generally serviceable (I believe) 049 MPS which should work for testing purposes. PM me if want help. In the meantime, I'd recommend at least two checks:

1. Thoroughly checking CHT, the connection, and the wiring all the way to the ECU.

2. Checking to see if fuel injectors are actually getting fuel and firing - pull one out and put it in baby food jar (or something similar) and crank the engine. Is there fuel?

I like my D-Jet, but I've replaced everything on it over the last couple of years in an attempt to get it working well. That includes fuel pump, ECU, MPS, wiring harness, CHT, T1, fuel pressure regulator, throttle body, TPS board, all hoses, etc. etc. Unless you're pretty well versed in modern FI systems, you're also going to have challenges. See the threads currently here on the board about Microsquirt conversions. It requires some knowledge, creativity, and patience to get that working on our cars.

Hang in there.

Both diaphragm were ruptured. So when I check the CHT do I check for voltage or resistance or both?

[BeatNavy]

Resistance. You need to check the following as a minimum:

1. CHT to ground at ambient temperature - check resistance from the lead to ground (e.g., negative battery terminal). Should be no more than 2.7K Ohms at today's ambient temps.

2. Make sure CHT is actually CONNECTED to the wiring harness. Inspect the connection and wiring to make sure it's not broken. The harness gets pretty beat up and nicked over 40+ years.

3. As a final check, if you're able, disconnect the ECU connector from the ECU and check resistance from pin 23 to ground. Should have same values as #1. There are 25 pins on the connector, so it's pretty easy to find pin 23.

You're MPS needs to be at least close to spec to work as well.