Testing Coil Connectors and Power Stages

[aeronautic]

Hey guys. Does anyone know how to go about checking the power stage, and coil connectors in a 94' 960? Which wires need to be tested, and what the resistance and other readings should be?

That's the short version of my issue. I'll post the longer version in my second post here in case anyone is familiar with the issues, and willing to give a bit more in depth response.

[aeronautic]

Here's the more in depth version, so that I don't turn anyone off with a lengthy post, and not get an answer the testing question that I can't seem to find very good info on anywhere.

I have what my gut instinct tells me is the engine wire harness problem that plagues a lot of older Volvos. I have a 94' Volvo 960 wagon with 168k miles on it.

I bought the car a few months ago to go on the road trip I am on now after getting laid off, and the previous owner hid the problem by clearing the codes on an OBD, just to have the check engine light come on a week after I bought it, with code 113 for injector group 1, and code 115 for injector group 2, as well as 212 (ho2) and 241 (ecr signal) which from what I gather woud be caused by the harness problem tripping it out. He claims to have never had any problems with it before, which I highly doubt.

I first started noticing the slight intermittent power problems when accelerating. Then while I was idling my way to a parking spot, the check engine light came on while I was just about to stop, but when I got back in the car later it seemed fine. Then as I took the car out on my trip it lost all power on the freeway while stuck in traffic, and multiple lights started flashing on the dash, and I had to crawl my way to the side of the freeway. Waited about ten minutes or so and tried to start it up, and drove it fine for about 20 or so miles to have the codes checked out, and this is where I started to to find out about the engine wire harness issue, as the mechanic said that's what he thought it was and that he felt the harness was a little loose, but sounded like he was more familiar with the issues on other models rather than the 960.

The problem went away for a while, and then happend a couple more times losing all power, only to start up and drive again fine, but then finally happened three times in a row, and did not drive fine after, and is now at the point where it can't drive down the block and I'm kind of stranded in Portland on my road trip trying to figure out the problem. I took it to a one man older swedish mechanic that turned out to be semi-retired, and not as knowledgable as I hoped, who told me he was convinced it was the air mass meter. This $400 part did not fix the problem, and actually made it more noticeable above 5000 rpm's with the engine puttering on the freeway with intermittent power surges.

After the original mech recommended Dave Barton's site, I started doing more and more research about the issue, and according to Dave (who seems to be one of if not the most familiar with the problem) the coil connectors are the first to go in the car, and that is usually the source of the problem with the 960's. I have the option of spending another $150 on Dave's wiring harness that would probably be smart longevity wise, but I'm not 100% that will fix the problem, and if I can get by just replacing the connectors on the coil packs, or insulating them better, it would help my bank account and allow me to do a more long term fix down the road.

But from additional research I did, it sounds like there could be other problems, either in addition, or as the source problem. The two power stages, the coils themselves, and poor solder points all could have problems with them, but my problem is diagnosing and knowing for sure what the problem is, as I do not want to sink a bunch more money into this only to be wrong.

I tried pulling the connectors out of the coil packs to look at them, but the plastic connector just slid back slowly, and the black insulation (orig heat shrink maybe?) just crumbled away, and the wires were exposed a little and don't look very good. They also appear corroded or stuck to the male part of the terminals on the coil pack as they don't come off when I try pull with a mild grip (trying not to break them off). They look pretty much like this.

http://www.davebarton.com/960-coilconnect.jpg

This leads me to believe this is very likely the case, and I have been able to find part number 3523813, which looks to be part of the wiring harness with the female bullet connector that could very likely be the culprit here. If that is the case, my next question would be how to splice it in? Just snip off the exposed part that was on the terminals, and crimp it with the new connector and heat shrink?

Anyway, my main question is do any of the knowledgable posters here know of a good way to diagnose whether the problem is the connectors themselves, an open wire somewhere deeper down the line, a poor solder point, the power stage, or the coils themselves? Specifically how I can check the wires at the connectors, and the power stage to see if they have the correct ohm's and volts with a multimeter?

My apologies for the long post, but I wanted to get across as much info as I could to help with the process. If anyone has some knowledge on the subject, it would be greatly appreciated.

[aeronautic]

Anyone with some experience testing the coil connectors, and power stages with a multimeter, and willing to share that info?

[Piet22]

It is true that bad coil connectors are a common problem now with the 960/S90/V90. However, your error codes seem to point to the fuel injection system and not to the ignition. Also, it is not so likely that multiple coil connectors fail simultaneously.

However, as a temporarily solution and to rule out this possible problem, you can just remove the plastic connectors and insulation material altogether and push the metal connectors directly on the ignition coils. If necessary, use pliers to squeeze the metal connectors a little bit to obtain a tight and secure fit. If the problem still exists you could replace power stages. They are available on ebay for about 50 dollars (search for V90 ignition control module). Again, I have never heard that both fail at the same time.

If the problem still exists you might want to check the fuel pressure regulator, the fuel pump or the fuel pump relay.

Piet

[aeronautic]

It is true that bad coil connectors are a common problem now with the 960/S90/V90. However, your error codes seem to point to the fuel injection system and not to the ignition. Also, it is not so likely that multiple coil connectors fail simultaneously.

However, as a temporarily solution and to rule out this possible problem, you can just remove the plastic connectors and insulation material altogether and push the metal connectors directly on the ignition coils. If necessary, use pliers to squeeze the metal connectors a little bit to obtain a tight and secure fit. If the problem still exists you could replace power stages. They are available on ebay for about 50 dollars (search for V90 ignition control module). Again, I have never heard that both fail at the same time.

If the problem still exists you might want to check the fuel pressure regulator, the fuel pump or the fuel pump relay.

Piet

Any reason why you would think those codes point to the fuel injection system? From my research, those are the same codes that come up when people have connector and coil problems. All the flashing dash lights that came on when the car first died on the freeway sound like an electrical issue, and the visibly crumbling connectors, and mechanic that thought it was the harness kind of point in this direction also.

I don't think all the connectors or power stages failed simultaneously. The car hasn't seemed to have the kind of power one would expect out of the inline 6, and I had noticed the acceleration sputter every now and then weeks prior. My guess is that it was having a connection problem for a while, but still ran ok, then with the heat lately, and the long hours I've spent driving on my trip, they started to deteriorate pretty quick.

They don't have to necessarily all be gone for those codes to come up. Just one from each injector group from what I gather. I would imagine problem has probably been going on for a while, and the previous owner hid the problem. But since the car doesn't have enough power to drive down the block now, that is why I think the heat and heavy driving have probably lead to most all of the connectors failing if that is indeed the culprit.

It's hard to tell if it was coincidence or not, but wiggling the wires on the #4 cylinder seemed to coincide with the engine smoothing out while it was iddling, but it still did not have enough power to pull away while driving. That same #4 coil and the spark plug chamber also had a smell of electrical burning to it that the other coils didn't have when I pulled them out. This however could be a seperate problem with the coil or the plug I'm not sure.

This isn't a great photo because my iPhone camera has deteriorated about as much as the connectors, but here are the wires going into the coil pack. The bullet connector insulation has melted and just slides back and crumbles away on the wires when the shell is unclipped and pulled off the male connectors. The wires themselves appear corroded or stuck to the male terminals, because I can't seem to get them off short of yanking on them or attacking them with a pair of pliers which don't seem look good ideas.

[mcnabbr1]

I'm experiencing the exact same symptoms as you, on my 2003 S40 1.9t 84k miles. Did you ever figure out the fix?

[93Regina]

2003 S40 1.9t 84k miles

Well now, here's a primer on Motronic 4.3-4, and via scrolling down this site's page, there might be some test info.