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740 Turbo drives like it is rev limited

I guess I was getting my hopes up about the wastegate. I couldn't get it over 2500 at idle, shut it off and messed with the wastegate linkage and within a minute restarted it and got my revs back. Whatever is rev limiting it seems to correct itself when I shut it off and restart it. Does that mean anything?
 
I do have a known tested AMM coming and a fuel pressure regulator coming any time now. Hopefully one of those helps.
 
It never hurts to do a solid tuneup as well. Clean injector grounds, clean resistor pack for injectors (VERY important since it is susceptible to constant moisture and corrosion. I have fixed multiple poorly running or non running 7/9 cars like this).

Plugs, wires, cap and rotor. All things that are probably overdue for replacement anyway. It's not firing the parts cannon either.
 
Cap, rotor and plugs are new. Not the wires. Main under car fuel pump and filter are new. All this was replaced by the Volvo shop. Also the timing was checked. They did get it to the point where it starts and runs. But still have the intermittent rev limiting and fluctuating idle. I will now look at the grounds and injector resistor packs too, now that you mention it.
 
It started recently so where I live it's winter. So usually cold and not humid or rainy yet. But a bit damp on the milder days when snow melts. I'm not noticing much difference in weather changes. It always has a flaky idle and seems to load up when starting and have to put my foot down to clear it when first starting it. Runs OK when warmed up. It doesn't miss. But the engine rocks at idle in gear. Not smooth. When I put it in park after taking it for a run the idle dives up and down but tries to idle at 1400in park.
 
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I would also recommend checking for any post AMM air leaks. There are lots of potential leak locations. The intake manifold is certainly one that could be hit or miss given engine temperature.
 
It started recently so where I live it's winter. So usually cold and not humid or rainy yet. But a bit damp on the milder days when snow melts. I'm not noticing much difference in weather changes. It always has a flaky idle and seems to load up when starting and have to put my foot down to clear it when first starting it. Runs OK when warmed up. It doesn't miss. But the engine rocks at idle in gear. Not smooth. When I put it in park after taking it for a run the idle dives up and down but tries to idle at 1400in park.

So running original LH2.2? Gotta say, I'm in the same boat w/ electronics and every year I think about throwing away the 80s brainless electronics for some sub $1k actual intelligent ECU stuff. Since I'm not an 80s Volvo mechanic with all their external ECU tools to diagnose these things!

Please don't discount the 4 vane hall-effect sensor in the distributor either. Definitely check its connection but more-than-likely that hall-effect is going out or finally at its maximum age. I had to replace mine with a "known better" unit about a year or two ago, which fixed a bad starting issue. I still need to install a brand-new one (which I do have) but I really just can't get over the pressed-on setup of them! Seriously time to get a supportable ECU setup I guess. :(
 
Yes, what surprises me after needing this is the lack of diagnostics on it. Can't get the fault codes that people with later systems get. It's a pain. It's our daily. It's been great until this issue or issues came up.
 
Latest development. Starting to occasionally puff bluish smoke from tailpipe. Mostly after idling then stepping on it. Tailpipe is black and oily. I haven't had much time but did pull the plugs and they are clean and dry.
 
I recently replaced the ECT. New Bosch unit. Known working AMM and fuel pressure regulator is coming in the mail. Hope one of those helps. Thanks for everyones input so far. I appreciate it.
 
Latest development. Starting to occasionally puff bluish smoke from tailpipe. Mostly after idling then stepping on it. Tailpipe is oily. I haven't had much time but did pull the plugs and they are clean and dry.


Does the turbo have 200k miles or so? Sounds like you have a few issues going on.

How many miles on the car ? is it well maintained ?
 
Does the turbo have 200k miles or so? Sounds like you have a few issues going on.

How many miles on the car ? is it well maintained ?

About 200k. I've only owned it for 2 years. Don't know the maintenance history. It's not a cream puff but not a total mess either. Ran really well up until recently then seems like these cascading issues the could easily be a combination of issues.
 
OP wondering whereabouts location of this Volvo Shop?

It's in Nova Scotia. The guy is really well regarded around here where I just moved. I wasn't able to work on the car myself because no garage and being winter. I took it there twice for not starting. Two large bills. To his credit he did get it to where it will start and run. But him advising me that I just have to hold my foot on the floor to start it after spending so much money with him didn't make me happy. I can't afford to take it back again with what he is charging and not finding the issues to make it right.
 
It's in Nova Scotia. The guy is really well regarded around here where I just moved. I wasn't able to work on the car myself because no garage and being winter. I took it there twice for not starting. Two large bills. To his credit he did get it to where it will start and run. But him advising me that I just have to hold my foot on the floor to start it after spending so much money with him didn't make me happy. I can't afford to take it back again with what he is charging and not finding the issues to make it right.

Yes understand. There is one called that near me in Ont that I wouldn?t ever go to so just wanted to make sure you weren?t burning $. Hope it works out. FWIW Nova Scotia one of the RWD Meccas (although I never did see that 240 when I was in the airport?)
 
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