familyman
Auto electrician bolted a new battery in. It nearly started immediately afterwards. But next try, no hint of starting again - cranking only - even with him cranking while I sprayed ether into the AMM pipe.
Going out soon to buy some pliers to disconnect the ECT sensor.
Major Ledfoot
You don't wanna contaminate the AMM hot wire. So ether ought to be sprayed upstream of the AMM.
RPM / crank position sensor is held in by a 10mm bolt Here's a easy view of it, without the heater hoses and a firewall in the way.
familyman
Thanks.
* Have the pliers now. But haven't found a way to get the ECT sensor plug off (let alone reconnecting it). So thought I could disconnect it's wire #33 at the ECU. Nope - requires a special tool to get the wire out without damaging it. So that's an ongoing saga.
* I just connected a small 12V bulb across the plug terminals of an injector. It flashes! So the injectors ARE firing.
So I have:
* Healthy flow of fuel coming out of disconnected tank pump
* Secondary pump pulls fuel ok from a bottle
* Fuel reaching injector rail is quickly returned to tank
* Fuel relay operating normal when: a) key turned on (both latched), b) then one side unlatches, c) both latched on again during cranking.
* Coil: windings test ok (not open circuit) and cranking flashes test light
* Spark present at sparkplug end of leads
* Injectors firing when cranking engine!
But... No start!?
Short of the injectors firing but being completely blocked, I'm lost. And even if that unlikely event were true... why isn't the engine starting anymore when using ether spray?
Although everything tells me the CPS must be ok - I'm going to test that with a multimeter across the plug while cranking.
jamesinc
Your engine might be flooded. Disconnect the injectors, accelerator to the floor, crank it for a good 20 seconds. If it starts sputtering, keep cranking until it stops sputtering.
familyman
Strange - just had to login again.
jamesinc;119139 wroteDisconnect the injectors, accelerator to the floor, crank it for a good 20 seconds.
Time of death 2:20pm. (No sign of life.)
jamesinc
Do you mean it's not cranking, or you just didn't get it firing up?
jamesinc
I would stop beating your head against it, the unknown is the ECT, until you disconnect it there's not much point trying to debug further. You have confirmed spark and fuel, and you haven't touched timing or anything like that, so the problem is almost certainly a sensor, the two primary candidates being the ECT and AMM.
Edit: I'm also having trouble understanding why it's impossible to disconnect... I know it's out of the way, but usually you can shove your hand back there and pop the plug off.
Ramrodfunk
I had a bad "ignition amplifier module". Near the battery on the inner guard.
It drove me crazy trying to find out what was wrong.
On a side note I broke about 50 meters from @jamesinc house but that was before I knew where he lived.LOL
Just thought I'd throw that out there.
I am still a noob but you never know.
familyman
Yes, sorry. ;-) Cranking fine on new battery, injectors unplugged, foot to floor, 20-30 seconds, not even a remote sign of starting.
I'll keep trying to find a way with ECT, but I'm confused... Have spark & fuel... So if it were faulty, wouldn't the ECU be cancelling the ground pulse for the injectors?
I'm going to test the other 3 injectors flash first too, since that's easy. ;-p
Oh - and earlier today I tried disconnecting the idle air control valve.
jamesinc
Have you tried disconnecting the AMM yet? That's a 10 second job
familyman
Grr... What am I thinking... The injectors have a common parallel connection. So if one has spark, they all do. [Sigh.]
familyman
Yes, have done AMM several times throughout this.
That ECT... I know exactly what you're saying. Because the pictures I'm seeing on youtube, etc. - I have a fraction of the access those cars show, due to having extra bits and pieces those cars don't seem to have. From the front I can reach the lock-on wire with a screwdriver to push it in - but the screwdriver takes up all the room so there's no way to push in the wire and pull on the plug at the same time. From the rear I'm completely blocked - can't even get a finger in. And from above (while I use the screwdriver to push the wire in) - which is my best (only) chance of getting it off... It's just not working. The pliers slip, the screwdriver slips... and when they both don't slip it doesn't come free because it's branch off the harness is about 3cm long - when I try to move it off the sensor, the thicker harness prevents it moving back off.
jamesinc
From the side? I.e. remove the inlet duct and go in that way? That's how you'd access it if you were pulling the sensor, from the side with a 19mm deep socket and a long-ass extension.
familyman
I'll look again. I think there was some reason that didn't work before. Back soon/later.
Major Ledfoot
Another tricky thing you can do with LH 2.4 besides checking for codes, is going into hardware test modes, so you get to hear the relays clack, the injectors click, etc.
familyman
Got it off! (Never get it back on again, but it's off.)
No start.
jamesinc
Now unplug the O2 sensor and AMM. All of them unplugged at the same time.
familyman
jamesinc;119160 wroteNow unplug the O2 sensor and AMM. All of them unplugged at the same time.
Couldn't find the O2 sensor at first. There's a single thick green wire and another two wires in a sensor fitting (black wire and yellow+red wire). I tried each one - individually and both unplugged - along with both coolant sensors and AMM unplugged. No go.
The ignition amplifier module Ramrodfunk mentioned... I noticed that hiding when I lifted the battery out yesterday. Can that cause this? (What were his symptoms?)
jamesinc
Yes, a faulty power stage (ignition amplifier) is definitely a possible cause of your symptoms.
https://www.fcpeuro.com/products/volvo-saab-porsche-ignition-module-3501921
A new power stage isn't heinously expensive. If you were going to do an FCP order, I'd throw in a crank position sensor too
https://www.fcpeuro.com/products/volvo-reference-sensor-rpm-240-740-760-780-940-271949
Maybe you can talk
@Slowbrick into giving you a second opinion, as I think he's not too far from you and he knows Jetronic pretty well.
gavinh
I'm sorry if it has already been mentioned but are all the timing marks aligned? It sound like it should be firing
