I finally got the ignition and fuel pump hooked up on my 76 2.0 L and the engine cycles between reving and stalling when I hold the pedal down to get a fast idle. What do I need to be checking now?

Pinched line, clogged filter, filter on backwards, lines routed wrong (engine bay feed and return swapped). Have you tried putting a pressure gauge on to see what it is? You can pull the line off the cold start valve and hook it up there. 29-30 pounds. Can also check inside your gas tank for crud and a clogged stainer sock. Valves adjusted properly? Timing and dwell correct? Idle air screw on the throttle body, have you tried turning that up? You also have an adjustment on your ECU. Clockwise enriches, counter clockwise leans. That typically has a melted in hashmark for where the factory setting is.

Double check your ignition wires on the coil as well as the rest of your spark plug wiring. If the wires on the coil are swapped your car will run like crap. A shop did that on my 75 years ago. Eventually fried the ECU before I figured out the problem.

the points go to the negative of the coil and the condenser and +12V to the positive side?

where is the adjusting screw on the ECU? There is a trim pot on the wiring harness back near the rear of the passenger side of the engine with a wire disconnected.

I hadn't thought about the timing. Good call on that...I just assumed that the PO hadn't changed anything while the motor was out of the car but he did change all the vacuum hoses. SO, I'll check timing and all hoses while I'm at it.

Thanks for the refresher...I haven't had to tune an engine in years. I used to do it all the time.

The fuel pressure holds steady around 30psi at the driver's side injector fuel rail.

On the coil (I have a 74 2.0), green wire from condensor (-) , black w/purple stripe (-), all black wire (+). Your all black wire may have a red stripe. Look carefully, sometimes the stripes can fade. Dwell = 47 degrees + or - 3 degrees. I forget the point gap. Maybe someone will chime in or you can check your Haynes manual.
There are also 3 white ground wires that attach to the case just underneath the engine latch. Check those as well. Transmission ground strap that attaches to the underside body (trunk pan).

On the top left side of the ECU, is your adjustment knob. Usually has a rubber cover on it the size of a dime. Regarding your trim pot, that's not factory. The PO might of had that hooked up to the cylinder head sensor on cyl #3. Check to make sure that head sensor is hooked up. That also can cause running issues. Hope that helps. At least your fuel pressure is good.

I have a wire connected to the cylinder temp. Not sure if it is the right one. There is what appears to be a brown wire in the bundle that resides near the distributor that I thought might go to some sort of sensor located behind the distributor towards the rear of the vehicle?

I'll check the wiring as described above and also try to determine what the trim pot in the wiring harness is all about. I've been hooking the less obvious wires to mating connectors in the same general vicinity. I know that is not a best practice but...where else would they go? Over on the driver's side near the front of the engine is another brown wire with a female spade connector behind the air pump. Not sure where that one goes.

Can you take some pics of this potentiometer you're talking about? There was a trim adjustment on the ECU but not one in the wiring harness. May have been some bandaid by the PO.

BTW, how is the normal idle? Is it smooth?

How does the engine run if you try to go to a high RPM like 2k, 3k?

Does it run good enough to drive it?

the idle is smooth but so low that it stalls out after 3-5 seconds. If I start it with not pedal and get it idling then try to give it some gentle pedal it immediately stalls out. So, I can't even get it out of the garage yet to try it out. I had it running enough last night with short idles to get the engine warm enough that coldness should not have been the issue.

Can you rev it up to 2k, 3k and stay running?

How about a pic of that potentiometer?

nope. When I got it to start with the pedal partially depressed I had to dribble a little gas in the intake to get it to start and then it revved around 2k for a few seconds and sputtered and nearly stalled and then revved back up again for a few seconds and then sputtered and then tried to rev again and stalled.

i have a 75 2.0 and had a similar problem. if you are running really lean, you may have a surge cycle like you described. The POT you are talking about is most likely someone put there because the CHT was out of spec and they were increasing the resistance to fool the ECU so that you can adjust the richness. have you tested your MPS yet? a bad MPS will cause lots of these problems. running rich will cause a slower idle but make sure timing i s spot on first. check the ohm reading of your CHT, make sure it is the right one and that is specs out for your car. my car would start and stall when i first go it because it would flood out, it was a bad MPS, but a rebuilt MPS sent to me that was set too lean was causing the idle surge you have, and i had to increase the richness setting and was good to go. - look at your spark plugs- are the sooty , or lite from running hot/ it really sounds like you are flooding out. DO a vac check on the MPS first.

phil

what and where is the MPS on these engines?
j

on the passenger side of the engine compartment - it has a vac hose attached ,
manifold pressure sensor- they fail eventually , either leaking due to lost seal, or the copper plate in side tears.

Aha! I'll take a look at that too. the wiring harness for that has a rectangular tombstone shape, with two adjacent corners rounded but the sensor itself has a socket with all 90 degree corners and the plug can be inserted in either direction. So...while I was trying both directions the entire plug body slipped off the four wires. Do you know what wire goes in which position?

you mentioned the wire from the distributor earlier in this thread.

that wire in a brown sheathing has another one of what your calling a rectangular tombstone plug end... it picks up the signal from the fuel injection points and tells the injectors when to open

without it no gas

often one of those 4 wires will brake, causing 1 bank to get gas the other bank not too

check that connection carefully.
the MPS, CHT, and Distributor fuel injection points are all Very important to the fuel injection system.

you may want to spend 4 hours reading the brad anders website that details all of the fuel injection componenets and how to test them.

read

http://members.rennlist.com/pbanders/DjetParts.htm

yes there is a wire from the wiring harness a single conductor with brown insulation. where do I plug that in?

Okay. I'll read and try some things tonight. Thanks!

Does LJET have an MPS? I thought it had a mass flow sensor.

The car is a '76. This would've been LJET, correct?

Do you have your oil pressure switch plugged in? It's just right (passanger side) of the distributor by about an inch or so. Theres a hole in the engine tin you'll see. You may or may not have the rubber boot on it. Actually that's the green with red stripes on that.

Check your email and foward me an email if you can. I want to email you a diagram that should help sort out all your wiring issues.

Quick side note, if you very carefully slide the sheath/rubber boots up the wires, you can see that each wire has a specific number stenciled on it. It will correlate to the number on your sensor in most cases. That will help you figure out which way your plug goes into your MPS. Those numbers are on the plastic that you match to. It should only go in one way, but maybe your wire connector was changed some where down the line.

Not sure,.
Ah, well i should read more careful. But l-jet info is there on p.b. anders as well.

duplicate post- darn phone!

- bill you have a 76 with
F.I., what say you?

you can email me at jdlmodelt@yahoo.com

75/76 2.0 liter motor is Djet Fuel Injection.

The key differences is the air injection ports in the head, the Cat convertor and unique heat exchangers, and the emmissions system.

The MPS and ECU are unique to the 75/76 model years, but Anders site deliniates all of that.

Rich

reving and near stalling on its own accord is also as 'hunting'.

did this engine EVER run for you?

print out the info from pb anders site and highlight the pertinent sections.

i'm afraid you are going to have to go way back and try to undo what you've done. don't be in a big hurry, try to be methodical in your approach. if you tearing into it you'll get further in the hole. you're going to be bombarded with lots of great possible solutions. first order of biz is to become familiar with wiring schematic. not the whole car! just the engine circuitry. get a camera take pictures and post them. it will speed things up for you

I'm reading thru all the troubleshooting that was provided by the above posted link. I have two wires that come out of the distributor. I have two wires near the distributor from the wiring harness. I have a coil. I am struggling to find pictures or wiring diagrams that are easy to interpret to determine where each of the wires go. There is also a condenser that is mounted on the engine sheet metal next to the distributor and there is the temp sensor near the distributor. I'll check the wiring for the injectors that comes out of the bottom of the distributor tomorrow when the sun has risen and the temperature has gone up a bit. IT is supposed to be 7 deg F below zero tonight. My garage is not insulated yet....so my furnace does not do much to heat up the garage space.

Two suggestions, one take photos of your engine bay and post them.
Second suggestion which is what I would do, is to very carefully remove your FI harness. Then label each connector on it with tape and mark it exactly as shown in the diagram I sent you; A, B, C, D etc.. Then, find each associate sensor, etc. and mark that area with tape and label it; A B C D according to the diagram; example "I" = coldstart valve. Then use the diagram as a check list as each piece is connected. That should help in getting it installed properly and minimize any connectors in question. Otherwise it looks like a birds nest of wires. Hope that helps.

Woohoo! I got her running! I determined that the fuel injector wires were mismatched on both sides of engine. I found all the little wire numbers just as described. I verified wiring on the air inlet and down near the bottom of the distributor, the wiring loom for the distributor connections and the head temp were routed wrong such that the head temp wire could NOT reach the sensor, so I rerouted that so all wires could connect like they are supposed to. I have one wire from the coil wiring loom that I don't know where to land. Where does the RPM tach meter wire to?

Engine sounds excellent! I was finally able to move the 914 over to the first car bay where the heater is so I won't be freezing my tail off anymore.

I am SO excited! Pictures later this weekend!

thanks everyone for all of the hints to figure this piece of the puzzle out!

It appears as though the pot was not tied to anything. just string tied to the wiring harness..I removed it.