Hello all. I'm pretty new to this forum as far as posting but have been reading many-many threads over the months when trying to diagnose problems with my son's Volvo 850 GLT. I must say, this forum has been a GREAT help. My hat is off to all you knowledgeable folk for the help you provide to others.

Ok, on to my latest problem.....we are dealing with a 93' 850 GLT 2.4ltr 5 cyl non turbo auto trans model. I'm pretty green at this so if there is other pertinent info. you need right off the bat please tell me what I need to provide and I'll be glad to give it (if I know it).

The problem seems to be a pretty common one for this particular model from what I've read here and on a few other Volvo Forums. To start off with, the car takes a couple turns of the key to turn over/start. Once running it idles just fine. But, when you go to accelerate it really lags, almost dies but not quite. If you feather the gas peddle it will slowly come up to speed and then appear to run fine for the most part. That's around town up to speeds of about 35 mph. However, if you are on the freeway the problem is even worse and has on 2 occasions actually stalled and died.

From reading tons of posts all over the place about these symptoms here is what we have done so far....
1.) Replaced the Fuel Pump Relay
2.) Replaced the MAF sensor (Mass AirFlow Sensor)
3.) Replaced the TPS (Throttle Position Sensor)
*The only code that we ever got was a 1-2-1 indicating the MAF Sensor which is why it was the 1st thing we replaced. Ever since then no new codes or even a repeat of the 1-2-1 has come up even though the car is still doing the same thing.

It seemed to be doing better for a day or two after these changes but is right back where it was before.

The latest thing we did just yesterday was a Fuel pressure check. I don't know what all you are supposed to do for a "complete" test so we just took readings at a fully warmed up idling engine. We only had 29 psi! I know it's supposed to be about 43 psi. Here's my question....how do I know if that means I have a bad Fuel Pump as opposed to say a bad Fuel Pressure Regulator? Any other specific tests we can do with those two things to help narrow it down?

Before ya ask, no, we can not afford to take it to a Volvo dealer (or any mechanic for that matter) at this point. Personal financial woes will not allow for that. Besides, I have read post after post of people who have had this exact same problem, have taken it to a Volvo dealer and after a few thousand bucks either still couldn't tell them what was wrong or just replaced about 5 or 6 things and never really know which one actually fixed it. So even if I had the money I would not feel confident in having this issue resolved. I have more faith in folks who have had hands on experience with this exact issue. Hope you understand what I'm trying to convey.

At this point my next step would be to replace the Fuel Pressure Regulator only because it is around $50.00 as compared to a new Fuel pump which range from $200.00-$400.00 depending on what and where you get it from. I wouldn't mind spending the $50.00 on the Regulator if I thought that was the problem and because it probably should be replaced any way, but, if it turns out that it isn't the problem that $50.00 would go a long ways towards a new Fuel pump. Know what I mean!?

Please forgive my horrifically long post. I promise to keep it short and concise when answering any follow up questions. If anyone has any helpful insights or suggestions I would love to hear them. Thank you very much for your time.

Bryan

 

This should be pretty easy; with the engine idling (fuel pressure gauge hooked up), temporarily pinch off the rubber fuel return line hose coming from the fuel rail. If the fuel pressure magically jumps to 43 psi (or beyond) then you need a fuel pressure regulator.

If it doesn't, then you need a pump and/or fuel filter (have you changed the filter recently?).

Not to wish you any ill will, but my money would be on the fuel pump.

Good luck!

 

I'm with gdog on this one. It's an easy test, really. It would definitely explain your "stalling and no power" description of what it's doing.

if you're tight on money, maybe you could check salvage yards for whichever part is bad. You'll wind up paying a LOT less for those parts. Are they new? of course not, but...if you KNOW what's wrong, you can still drive the car while you save up the money for a new one. A lot of junk yards give a 30 day warranty on parts, so that's also something to consider - it's not like the days when you bought something and it didnt work, and the yard said "tough luck."

 

Excellent info. guys. Thanks for your input. First off, I'm embarrassed to admit that we have not put a new fuel filter on yet and I swear that was the 1st thing we were going to do. Sooo....I will get one tomorrow, put it on, and report back. I'll also do the fuel line test with the regulator while the pressure gauge/tester is hooked up. Thanks again.

Bryan

 

I also agree with gdog, but one other way to see if the FPR is bad is to disconnect the vacuum line that connects to the FPR and smell the opening, if you smell gas, then the diaphram is leaking and the FPR is bad.

 

Thanks FCP, I'll give that a go as well!

Bryan

 

Ok guys I have an update for you! I feel like such an idiot but....I replaced his fuel filter with a brand new one about an hour ago and it seems we are 99% there! Currently the car idles smoothly and there is no stalling, lurching, or "dead spots" (lack of power) both with regular driving and also when "punching it". That's in town. The big test was when we took it out on the freeway. No problems accelerating up to full speed from 0 to-65 mph and also when punching it for passing. Unbelievable! Of course I'll feel better about it after he's driven to work for about a week to see how it does. He has about a 10-15 min. commute via the freeway every day so it'll be a good test. The only reason I say we are 99% of the way there is because it still takes at least 2 cranks (turning the key off and then on again) to start the car. Once running though it idles nice.

Per some suggestions by others we are also going to: Put in a new set of spark plugs this weekend and also pull the vacuum tree off and make sure it's good and clean inside. I think I'll try taking the fuel pressure regulator off so I can get to the vacuum line that has been mentioned and see if any fuel is leaking from there. I guess neither of the 2 black rubber hose/lines that I can see just looking at it (while still attached under the fuel rail) is NOT the vacuum line, correct? it must be coming off the bottom/backside (facing directly towards the manifold) which is why I'll have to take it off. Lastly, I may even get bold and see if I can remove the entire throttle assembly if it's not to hard and make sure it's good and clean inside to be sure nothing is gummed up and preventing it from opening/closing properly. Good idea or no?

Thanks again for all the help thus far. If you have any more suggestions/input I'm all ears. I'll report back with any new updates/changes and let you know how it all turns out.

Regards
Bryan

 

Is the starter turning the engine over briskly? If this is the original starter, might be time for a rebuild. Slow cranking was giving me hard start problems till i rebuilt the starter on my 850...

Shouldn't need to remove FPR to get to the vac line; I can see mine on lower left side of fuel rail (from front of vehicle perspective) just in front of the fuel rail cover. Slide the vac line off the FPR (vac line is smaller diameter than the fuel lines..) and see if there's any liquid fuel in there (per FCP). If there is, put a FPR on your shopping list.

As far as cleaning out your throttle body; not a bad idea (replace the gasket) but i doubt it's your starting issue.