Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Volvo s40 idle and rev up challenge

Hi guys,

I drive a Volvo S40 1999, 2L, none turbo, automatic.

I’ve recently bought a engine from Mike’s Place and i so regret and wouldn’t advise anyone to buy their.

The engine won’t idle smoothly and when I give Gas it misfire’ s and back fire.

The RPM only goes until 1300

I’ve replaced almost all sensors with new ones, both coil packs, plugs, plug wires, fuel filter, new clean oil, new water pump, new injectors, new starter.

Please help, I’ve spent R23000 so far :frowning: I don’t know what to do anymore?

Why did you replace the previous engine ?

Is this “New” engine new, used, rebuilt, remanufactured ? and yes, there is a difference between rebuilt and remanufactured

If you replaced it because it was doing the same thing the new one is doing, it could very well be that one of the parts you transferred from old to new is the problem, including the computer.

The old engine had a bearing knock but was still running

Sounds like a timing issue. Check to see if timing belt is timed. Then do a compression test.

Did that twice already…promise its not that

Curious on the compression test results.

Piston 1 2 and 4 showed 150

Piston 3 showed 130 but still in the green

That’s the results of the compression test

I’m still stuck on it being timing. Does it have VVT variable valve timing? I don’t know much about it, but you might do some research and see if something relating to that could cause timing problems. Another thought: with the new engine, can the ECM be trained to the old engine and needs to be reset?. Sorry it’s getting above my pay grade, and don’t have any other ideas other than over fueling. (Fuel pressure, injectors) hopefully someone with more experience will jump in.

Given the misfiring and backfiring I’m thinking there’s still some sort of ignition system problem going on. Are there any diagnostic codes? Was the engine computer replaced with one compatible w/the replacement engine? Didn’t the replacement engine have a warranty? Is there a reason you aren’t asking the seller/installer to do this diagnosis for you? The basic stuff for an engine to run pretty good (but not necessary perfectly) l include

  • compression
  • valve timing
  • healthy spark
  • ignition timing
  • fuel pressure
  • fuel injectors pulsed
  • throttle butterfly valve w/correct orientation & working correctly
  • throttle position sensor reporting correct position to computer
  • exhaust system not obstructed

Suggest to focus on getting your engine to idle and run “pretty good” as your first objective. After that you can work on “perfectly”. Replacing parts isn’t usually a very good way to solve this sort of problem. Suggest if you can’t do the diagnosis yourself, to ask for some pro help on the diagnosis, then you can fix whatever they turn up yourself if you like.

1 Like

The mechanic I have is also struggling although his trying not to show it

He said he will run diagnostics today

Also 1 more thing, the number 1 injector is over feuling although it’s a new 1.

The engine I bought came from Mike’s place in epping cape town and if they should fix it, I’d have to take out the engine again and give it to them then they will repair and give it back to me then I have to pay again to have it fitted

Could chase the over fueling, but ECM controls that also. Research if module is plug and play. Some modules need to have a chip inserted to match a specific vehicle. I believe some need flashed, or retaught.

1 Like

Thanks guys I’ll go through all of that today with the mechanic then I’ll get back to u

Do you get that American tv-detective show “Columbo” there in S Africa? Columbo’s famous for always saying “oh, just one more thing” to the person he knows did it. When he says that, you know that’s the key to the solution, and will eventually convict the perp. I’m guessing the number one injector problem may be the key to your solution too. The computer has no way to know that one of the injectors is injecting too much gas. All it knows is that the o2 sensor says there’s too much gas being injected , so the computer cuts the gas to all the injectors. That solves the over-injection on number one, but then all the others are getting too little gas. And the car isn’t going to run well like that. Suggest to focus on getting all the injectors to inject an equal amount of gas for a given injection pulse time. That’s measured with an injector balance test. If the injectors aren’t well balanced it will be impossible to get the engine to run correctly.

That’s an unusual warranty arrangement, but if that’s what the paperwork says, then I agree, you may well be better off to just use a shop who may be able to fix the problem without removing the engine.

Hi guys,

An update…

That mechanic tried everything u guys said and still nothing.

I’m trying another mechanic now and his diagnosis is that the computer box from S.A and overseas engines would never sync unless the computer box is recoded.

He took out the computer box for recoding and will return it tomorrow.

I’ll let you guys know what happens.

Hi guys, quick update

So the mechanic recoded/ remapped the computer box and upon putting it back he came across my fly wheel and crank sensor.

My car could not advance further then 1000rpm because the fly wheel was damaged.

Upon inserting the new engine the fly wheel damaged and bent a little out of range for the sensor to read it properly.

I’m having the engine lifted again to replace the fly wheel.

We are sure that’s the problem because when we played with the crank sensor the engine advanced to 3500rpm.

Thanks for your input guys.