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245T No more than 7 PSI

Maybe the wastegate is getting pushed open from a weak spring in the actuator?

Try to safety wire it closed, or use a hose clamp or something...? Keep an eye on the boost gauge and see where it goes.
 
Kjets On a Plane said:
Is the coil hooked up right?
I had one 240T that was the slowest 240T I'd ever driven with a coil hooked up backwards. Took forever to figure it out.
But it would really sputter at 7-8psi (though oddly smoothly).
What's the pressure at now? 84psi? What's the warm control pressure? 50ish at sea level or whatever?

I hate K&Ns and wouldn't use them on anything! Fine beach sand and the like goes right through them and can cost you an engine! And with a bunch of oil on them they're a pain to clean and probably more restrictive than just a clean paper filter. I'll just keep buying Mann/ Mahle made in germany dusty shelf paper filters and never worry!
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The more I look into this the more I don?t think it?s a wastegate issue it?s reqlly acting as if it?s starving for fuel after 7 psi, and or has a an intake restriction due to the metering plate not rising enough. As we speak I have the gauge on it again. System pressure is down to 87 psi and control pressure is hovering at 22psi on a warm engine at sea level which is very strange. The cars idle is not as smooth as it should be, you can hear slight variances in the in the tone of the engine, almost like a stumble of or richness and smells rich too. Think it?s a bad cpr causing this mayhem? With control pressure that low I can expect rich but how would that starve it for fuel in the top end?
 
Good grief. Sitting there watching the gauge and I started tapping the cpr with a wrench and control pressure rose to 40 psi before my eyes and stopped. Took it for a drive, same problem no difference, I get back and it’s still at 40. Close the valve and reopen and pressure drops back down to low 20’s and stays till I tap the cpr with a wrench again then it rose back to 30 and stops there. The bimetallic spring must be getting stuck or the cpr just doesn’t like getting tricked by the gauge.
 
The gauge hasn’t let me down before but who knows. I think this cpr could be bad or failing as the idle of the car and control pressure is much higher after driving for an hour than it is at first. It takes a long time to hit that sweet spot. When it was reading 20 the engine was burbling and running very rich then by tapping on it it was alleviated and the idle rose along with the control pressure.

Fuel pumps could be weak or getting low voltage, but how would I even test that? How about boost enrichment through terminal 7 on the lambda computer? Could that cause these symptoms?

I will wire the gate shut for the hell of it just to rule another thing out. But at this point it really is acting like it’s starving for fuel and has a massive intake restriction.
 
It does seem like it is more than one thing wrong. That is how my turbo was long ago when I bought it. Bad CPR, vacuum leaks from bad injector seals, split hoses, and a split intake gasket. Taking care of all the stage zero stuff like this really helped it run well.
 
Thanks for all the help so far. Solved the issue today, yes it was more than one thing. I returned that one shim I removed and brought the fuel pressure back up to 95 psi. After doing this it ran ALOT better and no longer acted like it was starving for fuel. My theory is that these Mercedes injectors require a bit more fuel pressure on our cars to maintain flow at a given psi and might have a higher opening pressure, this is just my theory though.

Next thing the car was still sputtering real bad under low boost, around the same point it was starving for fuel, almost sounded like it had a two step at times. I went back to the last thing I remember doing before this started and that was removing that stop in the distributor. I pulled it out, made a new stop from a nut and bolt and just like that the car no longer hesitated under boost and pulled hard to redline and simultaneously it started making boost like a mofo. Now everything works perfect.

Moral of the story is over retarding the timing is very bad and will break the whole cycle of building boost and make the engine useless as a pump. I know others have had better luck with modding the distributor but I would advise against it, probably not worth the gains considering the headaches it can cause. If you do mess with it don’t remove it entirely, just shave a bit off the side of the stop and call it a day.... What a mess.
 
Nice! So ignition timing was retarded? I have seen engines completely fail to rev when the ignition is pulled way too far back.
 
Kjets On a Plane said:
You have Mercedes injectors and a stock exhaust? :lol:
Did you say that before?
Thought the fuel system was stock...yeah the pop-off pressure is higher on those.

The stock Benz has one pressure pump gravidty fed from the tank feeding another pressure pump...
I wouldn’t expect your stock fuel pumps/tank arrangement/relays to last long with the pressure set above 95psi or provide stable consistent free pressure or components (like the WUR and/or frequency valve) to last very well from experience.

Id restore it to stock injectors unless you go way more wild with a larger exhaust and better intercooler etc, but to each their own.

All you’re really doing is just stressing the already marginal Volvo pump/relay/wiring arrangement out/hurting longevity with the line pressure set to 95psi, hurting fuel economy and longevity and under/over fueling it.

Also, the Benz injectors are probably fairly worthless for increased flow rate over stock 240TURBO depending on the part #.

Porsche 944Turbo are about the highest flow rate per cylinder injectors for CIS/K-jet Cars commonly/mass produced if you want to torture yourself turd polishing 240turbk k-jet for more power...

What about the Control pressure? You resolved that?

700T tank pump and the dual Benz pumps and a surge tank and/or old style tank no lift pump and Dual pressure pumps in series can help a lot.
One of the big 2 limitations of the 240TURBO Kjet is that it doesn?’t scale injector or line pressure to manifold pressure or control pressure to manifold pressure for boosted applications like say a Porsche 930, 944Turbo or Audi turbo coupe of the day.

Also there?’s a big flap restricting air intake flow...duh/:doh: :lol:

In reality if you improve the flow of the engine it?’ll make more power for less boost (head work, 90+ manifold, exhaust, exhaust housing or the turbo (cosworth or atp or different turbo) and stock intercooler really choke them a lot) and you?’ll actually probably want to run LESS line pressure is what I found once you address those needs. No point really changing the camshaft from the stock T with k-jet and all those restrictions either imo. All you?’re really doing is hurting economy, emissions, and usable power with almost no usable gains.

Further, you can make it plenty if not even a little over-fueled with that setup at stock 84psi line pressure (if that) with a better flowing engine at which point you?’ll eventually be lifting the airflow plate all the way up in the stock fuel dist at stock control pressure (even if you do hack/tweak s manifold pressure reference on it somehow).

Beyond that,
You?’d need a UTCIS (or moral equivalent) stripper motor controlled bigger fuel dist (semi-modern method) or to hack a higher capacity fuel dist/reshaped airflow plate bowl into it somehow or other with more flow capacity like the v8 Benz fuel dist or whatever (old school way) if one is insistent on costly/torturous kjet turd polishing,

They went thru so many variations to make the grp-a cars work right and hated it but had to keep kjet for rules. Forget about fuel economy (which was always marginal unless you drove a stick shift 240TURBO gently anyway), emissions and/or playing nice with cams with any reversion :lol:

But to each their own...
Not trying to be a jerk, just my own experience torturing myself with kjet 240Ts and futilitarian pursuits...
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Haha well I installed them years ago when it was time to replace my old ones. They were much cheaper than the Volvo stuff too and for what reason I don’t know.

I understand increasing system pressure stresses out that relay that’s not too great to begin with, tomorrow I will be installing a second relay in line to help take some of the load off of it. I plan on switching back to stock injectors in the near future. The control pressure seems to have resolved itself for now. Last I checked it, it read 48psi warm and never moved.

With this car as far as future mods go I have a worked head from my old 8v build it will be getting, a larger IC from do88 and 3” exhaust at the least. I’m not really trying to set the world on fire with this car, I have a 16v 242 and plenty of v8 stuff to keep me busy there. It’s just a really nice example of a 245t with new paint and new leather, kinda want to keep it original and “pure” in a way because truth be told there aren’t too many 240’s left anymore let alone many nice good running examples of 240t’s. I bought an nos York cci compressor for this car and charged it with R12 ;) I like that it all works like it should and If I can make it fast enough to keep up with modern day cars I will be happy. Plus I really appreciate Kjet from an engineering standpoint and to me the whole setup is just cool, yeah efi is way better but it’s boring and I just like old school engineering.

I read that there was an Audi cpr that came on the 5000’s with a pn ending in 094 that was boost referenced. Anyone ever adapted one to one of these cars? I know a guy locally that has a fuel distributor from a Renault 5 turbo on his 242 and that car was fast as sh1t
 
Glad you have it sorted out. You mean you know Tom Smith? His 240 turbo build is badass kjet. He used to post here a long time ago. If you really want big power with kjet. He can show you the way.

A little bit of tuning like you mention is decent and then above that you go with efi is the general accepted path as you know. I have enjoyed my 82 240 turbo with some moderate tuning for a long time. Mileage, no. Fun, yes. Awesomely fast, no but does keep up with traffic. I'm probably going to put efi in it sometime. But my 81 will stay stock kjet.
 
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dl242gt said:
Glad you have it sorted out. You mean you know Tom Smith? His 240 turbo build is badass kjet. He used to post here a long time ago. If you really want big power with kjet. He can show you the way.

A little bit of tuning like you mention is decent and then above that you go with efi is the general accepted path as you know. I have enjoyed my 82 240 turbo with some moderate tuning for a long time. Mileage, no. Fun, yes. Awesomely fast, no but does keep up with traffic. I'm probably going to put efi in it sometime. But my 81 will stay stock kjet.
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Yes I know Tom. Great guy, his shop is about a half a mile from ours. He?s done some fabrication for us in the past. Lots of cool Volvo?s at his shop.

I understand why people want to go efi, I just don?t think EVERY 240t on earth needs to be converted like a lot of people here feel. Aside from the terrible fuel economy a well maintained k jet system will meet or exceed most people?s needs and power and anything beyond its capabilities usually requires a transmission swap anyway.
 
Yeah I think my issue is I have a lead foot and fuel economy goes to sh1t after that. I often find myself asking is it really this hard on gas or is it just the 12 gallon tank that runs out quick:lol:

Another problem being I do a lot of interstate driving and that 3.73 gear is not kind to fuel economy. I love how they implemented a 3.73 and 3.91 just for 240t’s to try and mask the miserable off boost perfmance of the b21ft which only made it more impossible to build any boost in first.
 
Kjet economy can be reasonable but I never felt the need to get good economy when boost was so much fun. :cool: Plus both of my main cars gave up factory cams for V15 cams which are not what Volvo had in mind. I would suggest go with the above mentioned 3.54 rear diff if you wanted a bit more cruising economy. that is what the manual trans 740 turbos came with at least the early ones.
 
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