Okay, not much time but today I did get under the car to check the main fuel pump, filter and fuel lines and all looks okay. I had my son crank the car while I reached under and put my hand around the main pump and sure enough, once cranking, it clearly comes on. I could also feel the fuel rail energize. So, I crack open the main incoming fuel line, had him crank it over and fuel flies out unlike it did at the end of the rail the other day. I suspect my jumper wasn't quite engaging the pumps then because today it flew out there too when cranking.

I then pulled the rail and nothing out of the injectors whatsoever when cranked, just feel the rail being energized with fuel. I had no tester or anything but I assume there's no power to them because all being clogged seems very unrealistic although they look very dirty.

I don't believe this car has a Hall sensor and even if so I've got plenty of spark. I need to check for voltage at the injectors I guess and go from there.

There's 2 relays at the passenger foot well firewall and one I read is the fuel injection relay, the other a fuel pump relay. I wonder if that fuel injection relay is at fault?

Anywho, I wanted to give a quick update.

Thanks!

 

in the later cars, the fuel injection and fuel pump relays were all in the same relay. not sure about 83, thats like the first year for LH injection.... ok, looking for the 83 greenbook now...

... arrrgh, I am missing 1982-83. ok, going by the 84 book but meh....

hmmm, shows several different ignition systems. 1) breaker points, I doubt a US model has these.

2) breakerless electronic with vacuum advance on the distributor

3) breakerless electronic with vacuum advance on the ICU (this is the Chryslerr style our 87 has, too)

2) has a 2-wire connector on the side of the distributor for timing, while 3) has a 3 wire connector.

with either 2 or 3, the ignition coil pin 1 provides pulses to the LH-II ECU via a grey wire. the 84 shows seperate fuel pump and fuel injection relays, both 4-pin, both located behind the glovebox or passenger footwell area (vague drawing).

relay "E", the fuel injection relay, has red to pin 30, red to pin 86, orange and brown wires to pin 87, and a yellow-red wire to pin 85.

relay "F", the fuel pump relay, has red to 30, blue-red to 86, yellow-red to 86, and blue-green to 86.

hmmm, this drawing for the 1984 LH system doesn't even show an in-tank pump, just the main pump under the car. b ut this is probably just an oversight in the drawing.

the fuel PUMP relay provides the power to the injectors too (yellow-red wire). the other side of the injectors are switched to ground to activate them by the ECU (green-white wire).

 

You're a wealth of knowledge Pierce and a great asset, Thanks!

Problem is, electrical is not my thing. I swear this was somehow related to that alarm/siren/motion detector/immobilizer crap I removed. I just don't see how it effected the fuel injector circuit.

IF I remember, it's a non vac advance dizzy with 2 wires out the side. I have those 2 relays you mention in the pass foot well and they are smaller/different than those I've encountered before.

From what I've read ~ It's a negative/ground pulse that fires/controls the injectors but they only get powered when key is initially turned on for a few seconds and while cranking. From what I see, they are not receiving voltage otherwise, with key off.

I may get in over my head with this.

 

ok, then there's probably a vacuum advance thing on the bottom of the ICU (Ignition Control Unit). on the LH2.2 cars like our 87, thats mounted on the right fender just behind the headlight, the vacuum doohokey is on the bottom side of it.

and yes, per the 84 diagrams, the injectors get powered when the fuel pumps are on (eg, when the car is cranking over), and they are switched via ground pulses by the ECU.

 

I made a very quick stop where the car is on the way home [or my wife would have a fit as we have a dinner tonite w/ friends].

I verified the vac adv is on the base of the ICU

2 wires out of the dizzy

okay, bare with me on this next part..........

I took my test probe and when I grounded it at the clasp end and probed an injector connector I got nothing with ignition off, with key on or while cranking, on either side of the 2 prong connector

When I connected the clasp end to the positive battery terminal and probed the same fuel injection connector on both sides, I got a light with the ignition off, with key on and while cranking ~ always a solid light, no pulsing

I warned you my electrical exp/knowledge is horrible. I read to test them this way but I don't know why? To me, it concludes they're grounded?????

 

ok, well here's the circuitry that supplies power to the injectors...

battery+, red wire to 25A fuse, red wire to FI relay E pin 30, pin 86, and FP relay F pin 30.

FI relay pin 85 is grounded by the ECU piin 21 via a yellow-red wire to turn on the FI relay.

FP relay pin 86 gets coil power from blue-red wire from ECU pin 18. pin 85 gets grounded over blue-green wire from ECU pin 17. when the FPump "F" relay is 'on', then pin 87 (yellow+red wire) has power, and this branches out to: fuse 5; fuel pump; power to idle air controller; and power to the yellow-red side of the injectors.

if you were to remove the FP relay, and jumper pins 30 to 87, the fuel pump should turn on immediately, and the injectors should have power.

 

I followed these instructions I found online:

If the pulse comes on the ground side on your system.....

Check the ground side of the fuel injector with a "powered" test light for the signal. ( You supply the positive to the test light and the pulsed ground will allow the test light to light) If you have no pulse then check the computer to injector harness.

If you have a pulse then,

Check the fuses - if all of them are not firing then you have an issue common to all of them as you suspected with a relay.
Use the wiring diagrams above or your owners manual to track down the proper fuse.

Once you have tested for voltage at the fuse then follow the harness to the injectors for power. Once you have power and pulse it will modulate the injectors.

The power relay for coils, injectors, fuel pump, etc is only active when key is first switched on and then while cranking or running.

The injectors have a fuse of their own and it could be a chafed wire and blown fuse for the injector leg of fuel system power supply circuit.

Fuses can look OK but still be open.

 

I posted that as you were posting apparently.

I'll get back at this tomorrow but I've already tried jumping the fuel pump relay early on and no start although pumps did come on. That was one of the first things I did.

It seems to me by what you say, if the fuel pumps run then the injectors should work as well??

Why the 2 relays ~ one fuel pump relay and the other a fuel injection relay?

More tomorrow......

THANKS

 

the ECU is powered up when the key is turned on via the "E" relay, it monitors for timing pulses indicating the engine is turning, then powers the fuel pumps (via the "F" relay) ... if the engine stalls, it shuts the fuel pumps off a second later.

on later cars, like our 87, these two relays were combined into a single package (but they remained two relays inside).

 

Pierce, I went up there, jumpered 30 & 87 and the pumps came on like before but nothing to the injectors apparently. I took a good look at the FI relay 1 348 657 which is like a milky clear color and it appeared the terminals overheated as they are dark at the bases. The fuel pump relay is definitely a replacement with the newer 03 322 09 150 part #. Both of these 2 plugs are configured the same and would use the same replay.

I noted the incoming red wire is spliced [looks factory] a few inches before the relays, into 3 red wires ~ 1 to the fuel pump relay and 2 [one same size, 1 smaller] to the FI relay. Unless this smaller wire is a cut off that went to that alarm ??

I just can't see going any farther until I replace both relays. For under $20 bucks I can get 2 new ones on eBay and have them in a couple of days.

Beyond this potentially being the culprit, I can't really understand what else it might be besides the ECU, again under $50 bucks used on eBay, $100 reman.

This all started after the car ran perfectly then left sitting a few months as usual [he's a boater and goes for months at a time] and the battery died. It's never started since [this info is deemed reliable from the original owner.

 

Well, my son and I pulled the fuel rail up last weekend to see if there was and fuel, there wasn't. After all the other ideas, I figured it would be smart to just replace my fuel injection and fuel pump relays before going any further.

I ordered both on eBay Monday within the same state and figured they be here 1 or 2 days as usual for withing state shipments. Tues, Wed and today came and went and no relays.... I have off today so I figured I'd button up everything else including reinstalling the fuel rail so I'd be ready to try when those relays showed up.

I cleaned up all my tools on the floor, under the hood and trunk, re-installed the battery terminals and figured what the heck, try starting it again and.........................

VAROOM, it started instantly!

So, it was either prayer at work or those grounds on the intake were the culprit and simply removing them and tightening them later on re-assembly did the trick!

I've driven it around a good bit this am, started it 10 times or so and all is well.

I think I'll sell it and buy another Benz though.

THANKS!!!!!!!!!!!!!!!

 

gotta love the "I did a whole lot of nothing and it fixed itself" issues.

J.

 

Well, it's got a new in tank fuel pump now anyway and some questionable electrical wiring has been redone so not all for nothing and it certainly didn't fix itself

Thanks

 

Son of a %!+@#................ I took it for another ride this afternoon after posting, all was well and I was smiling. I went to move it about an hour later and sure as heck it just cranks and cranks again ~ no start!

I'm gonna call her Luci ~ short for Lucifer!

 

Curiosity on the brain.


I probed around an 84 Wagon and found nothing wrong with the car, as far as I can tell...
BUT....BUT...there was a test connector behind the cyl head that had burnt up... as the wires were resting on the engine block....recently burnt and feel it might have caused problems for the fellow who junked the wagon...

this guy maintained it...
new plugs wires and distributor cap/rotors etc.....I ENDED UP USING THE CYL HEAD ON MY 79....CHECK THE BACK OF YOUR CYL HEAD FOR THAT CONNECTION...
DO YOU HAVE THE WHITE DISTRIBUTOR CAP THAT SCREWS ON RATHER THAN CLIPS ON?

 

I see that wire/terminal and all is well. Black clip on dizzy cap.

I think it's got something to do with the fuel injection and fuel pump relays [2 separate relays back then]. I've looked a bit more closely........

I opened the 89 9672 1 348 657 relay and all looks well however the other 0 332 204 172 Bosch relay style is different, it's difficult to get on due to its design and something is rattling around inside if I shake it but I can't get it open [again due to its design] to look.

I have no idea what the original relays should be, I'm guessing the 89 9672 1 348 657 is original, the other a newer replacement. I have switched them back and forth on the 2 connectors several times throughout my attempts to start it.

I'm not going any further until I get new relays. eBay seller novoken has screwed me around since last Sunday. He claims they shipped Monday [from within the same state] but I still haven't got them. There's no tracking # to check/verify anything. I don't recommend this seller FYI.

Thanks

 

Okay.......... no relays yet but a very nice gentleman whom I contacted that has auto electronics experience got it going

He simply jumped what I think is the fuel injection relay ~ terminal 30 [big red wire] and terminal 86 [smaller red wire w/ blue stripe] and it fires right up every time. He thinks it's just the relay is bad so now I'm awaiting new relays in hopes this is the problem.

I'm not 100% sure I've got the correct relays coming nor if the ones that were there are correct?????

 

Just went up there again to see if I could get it to start by myself. I jumped the relay [it's still plugged in, just pulled apart a little for a paper clip to jump connectors] pins 30 and 86 and it fired right up just like he showed me.

I think when the auto mechanic/electrical guy was here it just shut off when the jumper was removed. When I just tried it, I reached over to turn it off with the key but it just kept running????? I pulled the jumper but I had to pull the fuel pump relay then it shut off [didn't try the key again]. I figured out that if jumpered it will not turn off with the key. I believe the relay started working after jumpering it several times is why it didn't shut off when I pulled the jumper. I started it back up without the jumper so the relay must have started working randomly?? Still awaiting relays but I believe the issue is relay related.

Still not 100% sure if I'm making progress except for the fact that it starts now and we've isolated it to this relay thus far. I was so excited that this mechanic/electrical guy showed up [I ran an ad on craigslist for help] and that it started and seemed to be just a relay issue.

 

sweet good to hear

 

Thanks!

2 new relays [fuel pump & fuel injection] and it starts every time and hasn't missed a beat