TPS Checks out. I could only wish I had the 2.4. Part of the problem is that I have to self-test everything I can to find the issue. Anywhere I look for parts for mine its listed "1987 Volvo 740 Turbo 2.3L". From what I gather, people in the Volvo community refer to it as LH2.2? I'm probably wrong there... but eh.

Finally got around to the throttle body cleaning. Looks Brand new. cleaned under the idle screw & all (the best I could). Then re-cleaned the IAC. It seemed snappier, now I'm just waiting on a stone cold start to see if anything is different.

The old gasket cracked into 3 pieces, bolts were slightly corroded, you could tell the TB hasn't come off in 50k+ miles if ever.

Curious though, under the valve cover it seems pretty messy, deposits and whatnot. What would you guys think about engine flushing one of these then refilling it with synthetic?

 

I've never used any sort of oil flush on my cars, but some folks recommend putting about 1/4 can of Seafoam in the oil, and the rest in a half tank of gas, then running the tank close to dry, refilling the tank, running a few more miles to get the rest of the seafoam out of the system, then changing the oil.

I ran a couple cans of seafoam through the gas tank on a Benz 300E I'm resurrecting and the oil was *black* after that, definitely time for a change. that car likes 15w40 or 15w50 in warm weather.

I've been using Mobil 1 10-30 in my b230ft of late, it seems quite happy with it.

 

Reconsidering the exhaust thing, do you know where to get a high flow cat for < $100?

 

The only cat I'd consider using on a European car would be the OE one. they last far longer than the aftermarket junk.

 

MagnaFlow 91005 High Flow Converter 2.25" Small Oval | eBay
An o.e. cat would be more than an 87 turbo's worth!

 

wait. I just re-read this whole thread. your weak running when cold could be the temp sensor, the LH ECU needs to know the engine is cold so it can run it a little richer...

also, 87 could be one of the years with bad wiring, peel back an inch or so of the outer cover of the wiring harness in a few places, and see what kind of condition the colored insulation underneath is... if its hard and cracking, bad news.

 

I was thinking temp sensor. Since its incredible smooth 60-70 degree days and kind of odd cold and hot days. Wiring looks good everywhere I've looked. If worse comes to worst, I'm pretty confident in my ability to rebuild the engine harness (givin the PN's for all the metal contacts. Im coming from a computer building/circuit repair/wiring background to the world of cars. xD I can give it a better look soon. The cat is exactly what I'm looking for.

On a positive note, It hasn't done its little idle surge / search and hunt business as of yet. In my opinion, I cant see how the crap in the throttle body would throw off air intake that bad if the plate still opens and closes properly. I could understand if the gasket was leaking, and in its condition it very well could have been.

 

building a wiring harness would be a huge pain.

you -can- get all the connector pins from Volvo, there's a couple pages in VADIS with all the PNs, and I even think you can still get most of the connector shells if you break one taking it apart... but yeeek, finding all the right sorts of color coded automotive grade wiring ? I'd hate to use generic few-colors wiring, be a mess to debug and later repair.

absolutely positively for sure, I would want the correct year Green Book Section 3(39) Wiring Diagrams for your car. I have the one for a 1992 740/940.

 

My thought process in rewiring would be to find or special order all the correct colors and gauges and replace one at a time as you would spark plug wires. As for the connector shells, I'd imagine if one cracked, depending on the damage you could glue/epoxy them. I'm also certain they'd be salvageable from other volvos in junkyards. I'd be very **** in using the exact lengths, colors, grades of wires. etc. Heating / soaking the connectors should make them somewhat more malleable. Wiring doesn't appear to be the issue at hand though. xD

 

Good wiring is definitely an art. I'm not patient enough. Tomorrow I'm installing a stereo in a 300E I'm fixing up for my wife (was going to be my daughters, but she thinks the 240 is hipper).

 

Ahh, my mother's friend has a 300e. It's in pretty sorry shape. I don't know where they were getting parts for it, but he said plug wires alone ran like $164. I'd definitely go for a 240 if it looked in good shape. I'd probably make it a rebuild project for a while though depending on its mileage and how well it was serviced.

 

mercedes dealer parts are kind of expensive. I got real german OEM* plug wires for like $80 via mail order. there's 6 of them instead of just 4 like our bricks....

This particular 300E is a 1990 with only 55000 miles on it. belonged to a friend's great aunt who drove til she was 92, it has a few exterior dents (she kept hitting stuff), but the interior is like a new car. my friend inherited it from her estate, and took it to various shops, spending $1000s without getting it fixed and gave up. I determined that the fuel injection was clogged up, I had to replace the air flow sensor assembly under the KE-Jet fuel distributor, and his $1000s of independent service had used really crummy plug wires so I replaced those with good Berg german ones as well as putting the right spec plugs ni it... a few cans of Seafoam, and it passed smog. its still idling a little rough, and the lambda control duty cycle is wandering all over the place, so I'm changing the O2 sensor next ($200+ from the dealers, $90 for a real Bosch one on the right harness from the internet).

*OEM meaning from the company that makes them for benz, not benz branded.

 

Okay so since the TB cleaning, idle has been steady but high. It starts and sits at 900, then slowly creeps up to 1300.

I found this in the FAQ
Except I don't see a blue and white wire. Would unplugging the IAC have the same effect?