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.

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.

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?

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.

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.

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.

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.

Original MPS
Primary coil 95.6 ohms
Secondary coil 350 ohms

Spare MPS
Primary coil 95.5 ohms
Secondary 343 ohms

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

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.

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.

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.

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?

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.

You may be getting enough fuel from the cold start injector to run for a second and then die. So, get four glass baby food jars, pull the injectors out and while they are still connected to fuel and power, place them all into the glass jars. Remove center lead from distributor cap and from coil to prevent any spark at all,
Turn car over for 30 seconds.
Do you have fuel in the jars?
Is the same amount in every jar?

So good news. I found the problem. The red wire for the pertronix was broken at the butt of the connecter. So now that I got it on. The car starts after putting my foot on the throttle alittle and I can drive it around and it'll idle but the idle will slowly go down until it stalls and dies. Any ideas on that?

Also I like to thank everyone for your help. I'm so grateful this community exist and I would be lost without it.

Still sounds like it's running too rich to me, but then again fuel starvation is also still a possibility. You need to start doing some tests to narrow your focus. The one Rich suggested above can help eliminate fuel starvation as the likely culprit. Any other evidence that it's running too rich? Smell gas? Wet plugs? Still could be MPS out of adjustment or not properly holding vacuum, CHT issue, excessive fuel pressure, leaking injector(s), etc., etc..

Another discovery happened. My relay board never Grosvenor and I believe was missing a relay. So I got a spare from German shops who had one and then bought 3 brand new relays. Second I check the plugs and they aren't wet but they do smell like fuel. Also the red G light is on every time I turn the key. Next step is to check the fuel pressure. I noticed that there is a screw on the fuel rail where it looks like I can put a fuel Guage. Has anyone tried that?

Yes, Joe ... the port on the injector rail is where you would attach a pressure gauge.

Another thing you can try, bypass the cold-start injector and see if that helps.

Click to view attachment
Awesome I'll connect it to a gauge then. Is the cold start valve next to the oil filler neck correct? Also here's a pic of one of the spark plugs, if that leads to anything.

The plug looks like you're running rich. Was is dry or wet?

... and yes, the cold start valve is attached at the front of the air plenum near the oil filler - it has two fuel hoses running to it (red thingie in the pic)



You can unplug the electrical connector and see what happens, and if that doesn't help, physically bypass it by removing the hoses and joining them together with an appropriate sized tube and tighten the hose clamps.

They were dry and I'm trying to find the valve right now. Also what is this since mine is disconnected.
Click to view attachment

That's your Auxiliary Air Valve (AAR) or sometimes called supplementary air valve. That lead is what warms it up so it will close after about 10 minutes of engine running. It is there to provide additional air the engine needs when cold (it is sort of a controlled vacuum leak that shuts itself off after roughly 10 minutes). If yours is disconnected your AAR isn't going to close (or at least not as fast as it normally would). That means you'll have a higher idle for longer than necessary. Given you're probably running too rich, that's probably somewhat off-setting the AAR not closing quickly (assuming the engine will run that long). Also, I believe if you ground that lead (hit it against something else) it's going to blow one of your fuses on the relay panel (IIRC) (and then your fuel pump won't run). I may be incorrect, but that's what I seem to recall. In any event, either hook that lead back up or don't let it ground with the car running.

The plugs look sooty. My guess is still too rich. I think the cold start valve is possible culprit (or one of them), but it's more likely CHT, MPS, or fuel pressure. Those just seem to fail most often and/or cause a rich condition that will actually kill the engine as it warms up.

You really should go here and read this site: https://members.rennlist.com/pbanders/djetparts.htm

So the resistance on the CHT is at 1700 and the fuel pressure is 30 psi when cranking to when the car is on. Maybe my pertronix is bad?

You are running full rich. I have not read this full thread. Have you put a vacuum on the manifold pressure sensor? Where is the knob on the ecu? All the way clockwise?

30 PSI is good.

Pertronix units won't fail intermittently ... if they die, they stay dead.

When you state your AAR is disconnected, are you saying the hoses are disconnected, the electrical lead is disconnected, or both?

bone up on Brad Anders' D-Jet troubleshooting tips

Did you check to see if the injectors are spraying? (into clear vessels)?

3 items are required to run ... fuel, air and spark ... (all in the proper quantities, of course)

Good question on the ECU knob, Curt.

He did use one of Tangerine's kits to repair the MPS diaphragm, which was apparently ruptured, but we don't know how much out of spec it could be at this point.

Thanks Rob. His symptoms are indicative of a poorly adjusted or damaged mps.

Joe, did you adjust the mps with a wideband O2?

Where is the knob on the ECU?

Haven't adjusted at all.

The electrical lead

He said he vacuum tested the MPS, but dang I still keep going back to the MPS too! (When that fails it cause maximum richness.) Maybe the hose is bad or not connected to the correct vacuum port?

Quick way to answer this: If you pull the vacuum hose off the MPS does it behave any differently?

The adjustment knob is located on the top, drivers side, of the ecu. It may have a rubber cover over it.

When I disconnect the hose the car intermittently starts to die.

I can still turn it clockwise.

From post #1 of this thread, I thought it was always dieing right after start? With MPS connected does it run longer? Is the behavior similar, or is it VERY different depending on that hose connection?

https://youtu.be/fpqJ-JvSSGs
Heres a video of what's happening. I couldn't make It in time to disconnect the mps.

Unplug the mps BEFORE starting it!

It's way rich!!

I guess to ask my question another way, if the MPS hose is disconnected first, does it behave differently upon/after start?

Like beat navy said on page one, you need a wide band O2 or some dyno time to tune the mps. Otherwise, you'll chase this forever. I'm not guessing. I'm speaking from experience.

Dang okay. I guess I'll get to work on replacing the tuning screw on the MPS. Also here's the video on the car starting with the mps vacuum line disconnected. https://youtu.be/vtgNhgLVtvs

Holy cow, if it runs that long with the MPS disconnected, I'd think there must be a massive vacuum leak below below the butterfly in the throttle body to keep it running as long as it did. I'm still trying to wrap my head around the idea that it would die sooner with the MPS connected. It sure sounds rich in that video with the MPS disconnected (as I would expect), but it should run better when you connect the hose. Unless the other end of that hose isn't connected where it should be? That hose should be pulling vacuum at idle, which would pull on the diaphragm of the MPS to lean it out.

If you start it just like that last video with the hose disconnected, then reconnect the hose before it does, does anything change as you reconnect it?

I hit another wall. I messed when putting in the new top screw so now the her opening stripped. Does anyone know where I can buy a used mps. I don't know how this happened. It was turning in so smoothly.
Click to view attachment

It's not a wall it's time to stop and take one step at a time.

There are plenty of cores around. I'd give you mine but I keep one as a spare.

You seem like you are in a hurry for this? If you are don't be.

Find a core and have Jeff Bowlsby set it up for you....cost you a little money....yes..but it will be near what is a stock setting. Make sure it holds vaccum to 12 psi at least and will hold that. You already know it shouldn't leak down.

Then make sure ALL the vaccum leaks are sealed. That car should not run with the MPS uplugged like that. The ECU would interpret that as WOT and gas would be coming out of your exhaust. So you have other stuff either not right .....or you have broken stuff that wasn't broke in the first place and have to start over.