Ok here goes, I bought this car a year ago, it’s a stock 1995 850 T5, I bought it with 82k miles on it. When I received it, it ran ok, but there was barely any boost. The boost gauge needle would barely get into the white range.

So I did some research on various forums, and I learned that the first thing to look for was the vacuum lines. I did that, and they were all busted, so I replaced each one with new ones and those leaks were gone. After that the boost was a little better, but it was behaving erratically. Whenever I would floor the pedal, the car would boost to like 8psi and even though the rpms were climbing slowly, the engine sounded like it was decelerating (sort of like a limiter kicked in and made it back down a bit) and it would fade to like ~4psi, and then the engine(felt like a limiter was bypassed) and accelerating kicked in and the psi would rise to about 7, power would vary during this.

So I thought there were more boost leaks, so after reading about some DIY turbo boost leak testers, I made one out of a PVC cap air compressor connector and tested for more leaks. I found a leak on the Intercooler so I plugged it up. I also found a couple of other hoses that were busted, so I replaced all hoses that I could. There were no more boost leaks of any kind. That didn’t fix the problem.

Then I figured the problem could be electrical, so I bought a new cap and rotor, plugs, and wires. I bought bosch wires, bosch platinum plugs, and the cap and rotor were some autozone brands. I installed those and then the car started misfiring. So after some research I replaced the plugs with bosch coppers and the misfire was gone. But the main problem still wasn’t fixed, same power surge. After messing with the wires a bit try to re-gap the plugs, one of the wires broke, so I re-installed the old bugicourds since new wires didn’t seem to help.

Then after some more research I read that it might possible be the CBV diaphragm, or the wastegate lever needed to be hammered down if there was a gap, so I checked and there was no gap, but I did get a new CBV and installed it and it didn’t change a thing. Now I was getting very frustrated.

Then I kept asking questions on forums and got varying opinions on what the problem could be. Some said that the ECU could be the problem, could be the MAF, could be the TCV, the CAT could be the problem(the car passed smog, so I didn’t think there was a problem), an O2 sensor could be bad, the fuel pump could be bad, low fuel pressure, wastegate could be fubered, charge pipes could be bad. So taking those into consideration, I got a MBC and installed it, the boost characteristics were different, but the same problem remained. I replaced the MAF, nothing changed. I got a custom 3” turboback exhaust with a new cat. I tested the car after that, the car built boost faster(but there was no power behind that boost, 12psi on the gauge felt like 5 before), so the same problem was there still. After that I thought it could be the ecu, so I decided I should get a ST Chip. I got the 17psi chip and I installed. I also got a FMIC kit and installed that, so all hoses are aluminum and are not leaking or collapsing under boost. The car felt the same, but now the car would boost higher, but the power still wasn’t there. I then got a fuel pressure gauge and checked the fuel pressure, the pressure was about 35psi idle, and like 55psi when I blipped the throttle, so it seemed normal. I then decided I should try a different wastegate, so I bought a t3 10lb wastegate and installed that, didn’t help. The car would boost to like 15 really fast and felt like the car hit a limiter again and then would sound like it wouldn’t let the rpm climb and the boost was falling again(but I was at WOT).

Now I was very frustrated. So I put back the old wastegate cuz there was no point in having it on, it was boost fast and high, but the car wouldn’t move. Then one of my friends said reset the ECU, so I let it reset over night and then i started to drive the car and the car felt different, it was more powerful, but not as powerful as it should be. It would hit 13psi and it would feel fast, but it would still bog like before.

After all this I gave up on the car and just drove it for like 4-5 months (I did change the PCV system for maintenance). Then after not boosting for like 4-5 months, I started punching the the car felt a lot better, it would boost to like 14-15psi(never hit 17psi that it was tuned for), and it would feel fast. Then after a day or 2, it went back to the same old problem. I had a local volvospeeder test out the car for me and he couldn’t figure it out either, so I gave up again. Now this last week the car got a check engine light and said the O2 was slow, and in my head I was thinking maybe the O2 was failing all this time and it just finally went and that was the problem. So I got a new universal O2 bosch unit and spliced it in, and it did not work. After this I give up again, I do not know what the problem is. Someone said it could be the tranny, but It feels fine and shifts fine and doesn’t throw any codes, and sometimes when the car pulls hard the tranny doesn’t feel fubered.. I even put some redline treatment in there just in case, and the fluid was pink before adding it.

And another thing, sometimes under part throttle when the boost would rise fast, I could feel some vibration coming from the engine bay, I don’t know if its pinging, knocking, detonation. And there are no codes or check engine lights.

So far , I’ve replaced:
Plugs, wires, cap, rotor, frontO2, MAF, CBV, PCV, vacuum hoses, tried MBC, tried different wastegate, exhaust(cat), added custom CAI, I added new grounding wires, custom FMIC, ST 17sp chip.

I really don’t know what to do anymore, I feel like I have to get rid of it, but I don’t want too, Ive put so much money into this car, lots of things have been replaced, the car has been acting like this since day one. Any advice is greatly appreciated.

I chopped up some videos of the problems in real time .

This first video is a shot of the tachometer. I am doing WOT runs in this and you will notice how the rpms stagger at around 4k rpms and the engine sounds like it hit a limiter and backing down, and then picks up again. During this period is when the car doesn't have any power really even though the boost gauge shows otherwise. sorry the videos were better quality before I uploaded them to Youtube, then they got a bit blurry.

http://www.youtube.com/watch?v=q_fDEmcxvQ0&fmt=18

Here is a video of the boost gauge during some of these WOT runs.

http://www.youtube.com/watch?v=G9_qtol0tGw&fmt-18

 

What about the injectors?

 

never looked at em, but won't it throw a code if they were bad or slow?

 

You need to wait until Tech kicks in.

In general, Volvos are not happy with non OEM parts. Universal-type O2 sensor is not a good idea on these cars; direct fit OEM is the only option.

I hope the attachment is of some use.


JPN

[IMG]local://upfiles/6892/2FF7FBBFADD8418ABE3F266894DEF82B.jpg[/IMG]

 

First thing to do it get that universal O2 out and get a direct fit on there.
Not sure about the tuning specs but OEM computer 15.5 lbs boost is fuel cutoff.

Is there any shaft play on the turbo?

You arent running a reverse intercooler setup are you?

Did you drive it with the fuel pressure guage hooked up? If so did the pressure drop off at all under higher boost?

 

I'll have to wait a bit to get the O2 replaced, but it was doing the same thing as the original even when the original was good.

I have a ST 17psi chip so it shouldn't be cutting boost.

I'm running a custom FMIC setup

no, only at idle i was testing the fuel pressure and i blipped the throttle a few times. What can of gauge should i get to test it while driving?

 

As long as the fuel guage has a hose that you can run to up by the windsheild it will be fine. You just need to watch it while driving.

Check with ST and see what the fuel cutoff on you chip is set to.

The O2's on these cars are really picky.

 

this is the o2 sensor that i got http://www.amazon.com/Bosch-15738-Ox.../dp/B000BZL08U

hmm, the fuel pressure tester that i used wasn't long enough, and it was too bulky. Are there any small gauges that i can try?

 

This one would be the best a little more money but the other looks like you still need to crimp wires which Volvo's hate.
http://www.fcpgroton.com/product-exe...ategory_id/170

Usually you can find one at an autoparts store. A generic one will work. It is the same setup as a Ford.

 

oh and another thing that could possibly be related to this issue, I can't check codes on the A6(ignition system) bank, no lights flash at all, not even 1-1-1. What could that be?

 

That might be in the computer or a ground. Does the light work at all when you press the button?
If not then remove the plate and open up the button and clean the connections and try again.

 

yeah the light flash if i press it, but it won't release a code.

 

Then it is either a connection or the ECU.

 

FYR.


JPN

[IMG]local://upfiles/6892/3C1FC1603EB54B009C9D05B7B3B0D626.jpg[/IMG]

 

Hey JPN, i tested the A box with a multimeter, the A6 bank reads out ~10 volts, but still won't release a code, does that mean its ecu?

 

It could be even though it isn't a real common problem.

 

i just did some testing on the TPS ,i was able to get 5v readouts from it so i don't think that is the problem, plus it gave me a code of 2-1-3 after i messed with it so it acknowledges that it's there. Now as far as the A6 bank, if it is in fact the ecu, how can it run normally besides that? Would that bank being faulty also not throw ignition related codes? Maybe i have an ignition problem and it isn't being reported by the ecu?

 

Possibly Can you get ahold of an ODBII scanner?
Does that read any codes present?

 

does it work with 95 cars? I know i have an OBD1, but i also have the OBD2 port, i just don't know if it is even hooked up.

 

Yes it is hooked up. A scanner will only read engine codes though. You cannot read tranny codes through it.