Cj1992
Hi i know allot of you have probably had this question asked on here many of times but the issue i am having with my 740 turbo is a power issue to the ezk unit its running lh 2.2 with ezk 117 considering a MS swap btw but the problem im having is im not getting power to pin 6 on my unit i can run a jumper wire off the ignition to the unit and everything will spring to life but once i start to drive the car it will stumble for a second every now and then continue to drive it seems to be more under load when i shift from second to third and etc ive replaced the powerstage distributor plugs and leads im at the stage now where ive pulled all my dash apart and chasing the wiring looms would anyone have any suggestions or experienced a similar thing?
Vee_Que
Where are you located?
I usually have issues with the wiring to me distributor hall effect sensor. I made a patch section and has no issues since. The wiring was all crunchy and under power would pull on the wiring and it would die.
That's on my 88' 740 turbo which I have a thread on in the rwd section.
Cj1992
Im located in wollongong NSW i examined my cable between the sensor and icu a little while back and it was pretty sad but didnt appear to be broken or loose the issue started about a month ago had really heavy rain and the car didnt want to start so i pulled the coil lead off and blew the moisture out and it started straight away but the next day managed to drive around without any issues until it came time to go to work got half way there then the car started backfiring when coasting down hills and wouldnt drive under 75% throttle and shortly after died and didnt want to restart to put a long story short.. i checked the icu voltages and found i wasnt getting power to the unit so i jumpered power to pin 6 then i managed to get it to start im just wondering wether there is a hidden connection thats become corroded somewere or maybe my ecm might be a bit sad..
Slowbrick
First things first. Check your grounds. Nothing will work properly with shitty grounds. I know you said you can jumper it to life but that doesnt explain why it isnt working in the first place. LH2.2 is a pretty simple system. Get a multimeter and start chasing circuits :)
Cj1992
Yeah thats very true ive heard their grounds can be quite a let down in some cases, and yeah me and the multimeter have been quite good friends lately ive managed to single out the ezk circuit ill take a closer look at it tomorrow when i can see it all again. Does the ezk and ecm power through the ignition switch or do they receive power from somewhere else in the engine bay?
nickm
Along with what Alex said.
Fuel pump and/or injector "radio suppression" relays are also a big problem in these cars.
Also check the fuse holder/thingy. That is not burnt.
Cj1992
Yeah ive checked all of those ive replaced the inline pump with an 044 and the RSR has been replaced with a 40 amp relay they both seem to be working when i bridge power to the icu and unfortunately my fuses have suffered the infamous overheating but ive cleaned up all of those contacts and ran a few new wires but the problem was happening before i done that just leaves me clueless sometimes on what else it could be i havent worked on an efi system of this style before
nickm
if pin 6 has no voltage then trace back with a multimeter
check for continuity (pin 6 to fuse) and voltage
volvoclub.org.uk/tech/fuel_injection/740-89-9.shtml
Cj1992
Thanks that actually helps allot ill go over it in the morning and see what i find. :)
Vee_Que
If the car isn't running. Try the wiring again near the head for the dizzy by wiggling it. If the car starts (power to ezk). Then you have your culprit. Efihardware.com.au does the correct connector. Just need two core shielded cable then a water proof connector just near the strut tower. I've had these cars for many years and it's usually this issue. Especially after rain. Have you inspected the inside of the distributor for oil leaks too?
Cj1992
I managed to get the car to start without a jump wire I found that I only had 1 wire under the fuse 13 was burnt out which I thought was rather strange so I cut it back and resoldiered a new piece back in and ran a wire from fuse 14 to 13 checked my voltages and found power at pin 6 plugged ecm and icu back in and she fired up I'm unable to drive the car at the moment to tell if the stuttering problem is resolved due to getting my heater core repaired but once I get it back together I'll take it for a run and see how I go.
Vee_Que
Interesting. Wonder how it burnt out so severely? You should put a thread up of your car in the rwd section!
Cj1992
Im unsure of how it came to be i have noticed there has been some previous electrical work on this car from the previous owner even the icu and ecm have had parts replaced by the looks of them and sorry on the previous response i replaced the dizzy complete about 4 weeks ago , yeah i might have to start another thread this thing has been a nightmare i seem to get it going good for 2 weeks then something else will happen to it lol..
Cj1992
Oh and needless to say the typical non working fuel guage...
nickm
The gauge is generally a sticking needle.
Vee_Que
Tapping the dash fixes that I've found!
Cj1992
Yeah it started with that then eventually went to not working at all getting correct voltages and ohms at the cluster points even resoldierd the fuel guage contacts and joints had a few bad ones but they all cleaned up good but still no luck dead as a dodo im thinking of going to pick a part soon to see if i might be able to scrounge around for hopefully a live one
