[i_like_volvos]

I guess its called an Evap hose? Looks like it only come as a single part for like $100... Was hoping just to replace the cruddy hoses. Anyone replaced this before?

Curious if you replaced these hoses and if so, what is the size?

 

[gr1m_reaper]

Blake you didn’t confirm what you observed when the motor is idling and you move the maf harness around. Same deal with the injector harness. If no change in idle rpm or quality, did you replace every inch of vacuum hose? If not you know what to do. Could be a tear in the turbo inlet hose so look there. Spray carb cleaner in suspect areas with it idling. Idle increase gives you clues where to look further. Does it idle smoothly and evenly? Check the exhaust tip for this. Is the hood shaking or is it rock solid with the thing idling? That’ll offer signs of poorly firing cylinders. Does the idle hunt or is it just steady but high? Put up a video. Prob get more help. Resetting the ecu is another option and how does it behave thereafter? Check the quality and tone of the injector pulse by using a long screwdriver up against each injector’s base and listen to the handle in your ear. Good for now? I’ll read your whole thread since admittedly I just jumped in. I’d do all of this before buying a jy maf.

Oh yeah, I did try to move the MAF harness around but did not notice any changes in the idle. The engine probably did not run long enough to know for sure, though. I will definitely try all of these other suggestions!

 

[gr1m_reaper]

Curious if you replaced these hoses and if so, what is the size?

i did replace them, but to be honest i don't remember what sizes they were - i just took the check valve pieces into the auto parts store and tried every hose til i found the correct size. kind of interesting, the nipples on each side of the valve were different sizes and required different hoses. i'll look again to see if they size is on my receipt or the tubing itself.

 

[gr1m_reaper]

i read somewhere that if the rpms go up high when the MAF is disconnected that means a vacuum leak somewhere. can anyone confirm this? this idle problem was not present before i started this thread, so i'm leaning towards a screw up on my end somewhere ....

 

[gr1m_reaper]

just thought of something... at the very beginning when i was replacing the PCV... the oil trap has openings for two hoses on the top - the shorter hose slips in between the manifold and goes to the top of the engine, and the longer hose goes behind the manifold around the engine to the PTC. does it matter which hose goes to which opening? sounds like a dumb question, but i noticed that it was one way on the car already (short hose to the left opening of the oil trap, long hose to the right opening), and the other way on the FCP tutorial video i was watching.

i switched it back and forth so many times contradicting myself that i can't remember how it is now. but if it definitely makes a difference and possibly the cause of my issue, i will get back under there to double-check.

 

[UT OLI]

Facing the front of the car, the right connection runs underneath the manifold and the left snakes up through the manifold

 

[gr1m_reaper]

I cant remember which i ended up going with, which sounds like I'm getting in there to check!! Please tell me this could be the reason for my issue??

 

[gr1m_reaper]

UPDATE - So since i couldn't remember how i set up the oil trap hoses, i removed the fuel rail and peeked down there. Turns out i did it correctly! That was a relief. When putting things back together, i noticed the throttle sensor harness was disconnected! Plugged it in,started it up - still a rough idle. However, when i unplugged the maf and started it again, it ran much better. No longer the super high rpms like before. So clearly the throttle sensor was the cause of that high idle problem. Does this confirm the maf/harness is the issue?

 

[98v70t5man]

After reconnecting everything reset the ecu so it’ll use the default fuel trims and see how it behaves.

 

[gr1m_reaper]

After reconnecting everything reset the ecu so it’ll use the default fuel trims and see how it behaves.

What is the correct method to reset the ecu? I've seen various suggestions

 

[JaredR]

What is the correct method to reset the ecu? I've seen various suggestions

Disconnect the battery

 

[98v70t5man]

...or use a scan tool.

 

[gr1m_reaper]

I disconnect the battery each time i work on it, then reconnect it when ready to try starting it up. Does it need time to reset with the battery reconnected prior to starting up?

Other people mentioned putting the battery cables together while disconnected, or touching the negative to the positive while attached, or connecting the terminals in a specific order, or turning the key to on position before reconnecting the battery, etc. ??

 

[gr1m_reaper]

Also tha scan tool i got appears to be worthless... Literally tells me nothing even when i disconnect the maf and see the CEL on.

 

[98v70t5man]

Applies to most every obdii car. Disconnecting the negative terminal of the batt for more than about 6 hrs will assure the system is completely discharged. To expedite discharge, remove both batt terminals and touch them together for 30 sec.

 

[gr1m_reaper]

No luck

 

[98v70t5man]

So the high idle disappeared once you found and fixed the disconnected tps but it still runs rough after resetting the ecu? Does it stay running on its own long enough to throw a code?

Were the fuel injector orings in good shape and you used one on ea side?

You certain you have the ignition sys aligned with the firing order? Did you replace the dist cap and rotor?

If you disturbed the ecu, assure it’s connection pins are not bent.

Did you replace the spark plug wires? If not confirm no high resistance exists in each cable when bending each one around. Include the coil wire in your checks.

Check every vac hose including the hose from the turbo inlet pipe down low to the RH side where it hits the fuel pres reg near the steering rack. And the vac source elbow in the pcv circuit on the RH side of the intake man. Make sure that’s not flopping around.

If your model has the sas emissions system, check the entire circuit’s hoses and lines for cracks to include where the valve connects to the exhaust stream and also look upstream at the air pump and its connections to the air box. You may have bumped parts of it while working in there.

I’m assuming you’ve pretty thoroughly ruled out an electrical short in the various sections of the harness you were working with. Easiest way is to move things around to see if the motor’s idle improves.

If the motor ran fine before the service you did it must be something in front of you under the hood causing the rough idle. Something like a maf does not just stop working.

 

[gr1m_reaper]

totally agree - has to be something i did to cause the issue. I managed to take a running car and turn it into a non-running car! i'll respond to each of your suggestions - hopefully we can figure this out!

So the high idle disappeared once you found and fixed the disconnected tps but it still runs rough after resetting the ecu? Does it stay running on its own long enough to throw a code? ---> correct, the high idle is gone. when the MAF is connected the engine runs for like 2 seconds and dies. But when the MAF is disconnected, the engine does idle but not very well.

Were the fuel injector orings in good shape and you used one on ea side? ---> replaced the o-rings, 2 per injector. Also replaced the basket filters and pintle caps.

You certain you have the ignition sys aligned with the firing order? Did you replace the dist cap and rotor? ---> replaced the cap and rotor exactly how it was on the vehicle before. will check again to be certain.

If you disturbed the ecu, assure it’s connection pins are not bent. ---> i didn't see anything out of the ordinary. will check again to be certain.

Did you replace the spark plug wires? If not confirm no high resistance exists in each cable when bending each one around. Include the coil wire in your checks. ---> replaced the plugs (genuine volvo) and wires (bougicord) in the proper order. will check again to be certain.

Check every vac hose including the hose from the turbo inlet pipe down low to the RH side where it hits the fuel pres reg near the steering rack. And the vac source elbow in the pcv circuit on the RH side of the intake man. Make sure that’s not flopping around. ---> this could be part of the issue. will check again and take pictures to see if anyone can see something incorrect.

If your model has the sas emissions system, check the entire circuit’s hoses and lines for cracks to include where the valve connects to the exhaust stream and also look upstream at the air pump and its connections to the air box. You may have bumped parts of it while working in there. ---> this could also be part of the issue. i replaced two of the hoses on the evap line (mentioned earlier in my thread) from the t-connector to the check valve and then on to the bottom of the turbo inlet pipe. will check again and take pictures to see if anyone can see something incorrect.

I’m assuming you’ve pretty thoroughly ruled out an electrical short in the various sections of the harness you were working with. Easiest way is to move things around to see if the motor’s idle improves. ---> agreed, i moved harnesses around and did not notice any changes.

If the motor ran fine before the service you did it must be something in front of you under the hood causing the rough idle. Something like a maf does not just stop working. ---> agreed. MAF was working fine prior to me working on it and stored safely on the workbench while out of the vehicle. but since the engine idles differently when the MAF is connected/disconnected, I'm assuming the issue is airflow somewhere in the system.

 

[98v70t5man]

Spend some more time triple checking everything, Blake. I know it sounds frustrating.

The sas and evap are completely separate systems. Check hoses and lines and elbows from bow to stern.

Like ya said check every vac hose and fitting. You may have cracked a plastic check valve or tcv or even the plastic filter in the evap sys or a line at the charcoal canister. Feel for air escaping of being sucked in. Oh and the evap hard line that runs between the sway bar as it exits down low from the LF fender area.

The fuel injector rebuild gives me pause. I never recommend a diy repair of this component due to the crud you can get in it without proper equipment to flush it. Gives me an idea though. With the maf unplugged, and the motor idling rough but at least idling, put a long screwdriver to each injector and the other end to your ear. You should hear consistent similar pulses at each of the five. You may find one pissing blanks.

If nothing I’ve given helps, try to put up a video. I’m not entirely sure from your description so far as to what kind of rough idle we’re dealing with. Hope I’m not driving you nuts. Oh and the maf harness connector gets abused so be very certain you’ve ruled out that connection. Get in there well away from the fan and move that bundle around.

-Paul

 

[gr1m_reaper]

I wish I would have left a lot of things alone - reading all the threads had me thinking "well I might as well do this while I'm in there" and now here we are...