Got a sputtering 1990 740 GLE. Does it more and loses a lot of power when running cold, esp. on steeper hills. Does it when warmed up, yet not as bad, but still loses power on hills.

-replaced fuel pump and filter last year
-mech cleaned out gunk from air intake at same time
-a different mech replaced plugs and plug wires year before that.
-my ex drives it and she was putting 87 octane non-ethanol gas. I told her to put 92 octane in it, which I think last tank was.

could it be fuel injectors? water in fuel? ignition coil? distributor?


Thanks in advance to anyone with ideas!!

 

Well, all these replacements are fine but these days especially you have to watch what brands go into these things... For example wires should be Bougicords, plugs can be crucial, some brands should be avoided, have to be correctly gapped, etc.
When did the problem start? Suddenly or gradually?
The parts you mention should last longer but if not quality components they may be due for a change.
90% of the time it's something simple and less exotic than "water in the fuel", but it could be a distributor cap, could be coil, etc.
Basically you need a "tune up" first, go from there.

 

Ok, I'll check the plugs and distributor cap first.

Any clue from being worse when cold?

 

GLE, is that a 16V (twin cam, DOHC) ? or just a regular B230F ? is it a Bosch LH 2.4 or a Regina system?

 

It's a 16 valve, B234F. Not sure about Bosch or Regina, I'll check. I thought it was Regina.

Forgot: power has never been great, but figured it was just due to being old car. It's sputtered a little, stalls every once in a while, less these days. This sputtering has gotten progressively worse over last month or so.

Had issue with starter wiring, mechanic installed a bypass switch after he realized starter motor was fine. Don't think this is related to sputtering, but just thought it worth mentioning.

 

Would running pure 87 octane gas then switching to 92 octane 10% ethanol (Costco) cause this?

 

afaik, the 16Vs are all bosch. never actually tinkered on one, however. Regina cars have a ignition coil that looks like a square transformer, while Bosch cars have a beer-can cylindrical ignition coil. Regina integrated the ignition power module into the coil, while Bosch uses an external power module. Bosch LH injection uses a MAF/AMM to measure how much air is going in, Regina cars use an air temp sensor but guess how much air based on RPM and throttle position (and they have a throttle position potentiometer which could go wonky and make for eratic running).

16V engines are high revvers, they develop their power at the top end of the RPM range. they are much smoother at high RPMs than the regular B230F engines, as the 16V's gained counterbalance shafts.

 

octane too low for the car could cause pinging under high loads. these engines all have knock sensors, if they detect pinging they retard the ignition til it stops.

the regular B230F engines run fine on regular 87. the turbos prefer premium (91 or 92) but tolerate regular. I dunno about the 16V's.

10% ethanol shouldn't hurt anything, although it might lower fuel economy by 5% or so.

 

So, I checked the HT wires and one came out kind of loose and had whitish corrosion, so I sprayed some battery cleaner on it and scraped it out. Seems to have done the trick. Stuff corrodes fast here in Hawaii. Have to clean my battery terminals if I leave car sitting more than a week.

 

get yourself a set of Bougicord spark plug wires, and use some silicone dielectric grease on the rubber parts where they fit over the distributor caps and the spark plug bodies.

 

So, today she says it's doing 1/2 power up hills. And making "a different sound", not the same sputtering. Sigh.

 

at this point, we don't know whether its spark or fuel delivery (or something mechanical) causing this problem.

a weak power module (this sits between the ignition control unit and the coil) could cause weak spark at higher RPMs, which could cause bad combustion... try this? pull out the fuel pump relay, then pull a spark plug, reconnect it to the wire, use insulated pliers to firmly hold the metal side of the plug against a engine ground, and have a friend crank the engine over, verify you get a big fat spark and not a weak yellow one. repeat this for all 4 spark plugs. also inspect the plugs while you're at it... you can find pictures online of what good and bad plugs look like, they should be medium grey, neither powdery white (too hot) or black (too cold). they shouldn't be greasy/oily.

has the timing belt been serviced? B234F 16V engines fail catastrophically if the timing belt breaks, the valves can impact the pistons, which can bend valves and/or crack pistons, which pretty much means trashed motor, rebuilding it is way too expensive... while rare under normal circumstances, if the camshafts are off by a tooth or two, you can seriously loose power.

has anyone done a compression test in all 4 cylinders? bad compression would mean crummy running and lack of power.

 

My friend/mechanic gets back on Tuesday. I was planning on having him do timing belt anyway, so good call. And I'll get compression test too.

I will try spark plug test. I'm concerned too that plug wires that were put on in 2011 were cheap. I've been reading about Bougicords, can't seem to find on the island. Everything is harder to find and more expensive in Hawaii.

Thank you again for your suggestions!

 

Update: got oil in 2 or 3 of plug cylinders. When I put plugs back in, no start. was freaking out, called a mechanic i trust. He told me to try pouring Restore in cylinders, turn engine over for 30 sec., then put new plugs in. Said it worked on another Volvo where oil was getting into plug cyl.
So, did that, started up and purred nicely. Drove and burned off smoke from Restore. Seems to be making different sound, not totally smooth, more like my '68VW Bug with its muffler knocked off. Power up hills not great, but it wasn't limping along. I'll get more news from my ex who drove it home.

I know this isn't great, yet now seems problem is isolated.

 

I'd compression test this motor before you waste much more time and money on peripheral things.

If this car has unknown history, its quite possible its been subjected to some hard core abuse and the engine is a basket case. its far cheaper to find a good engine in a junkyard car and swap it then it is to rebuild your engine, unless you're prepared to do a full engine rebuild yourself..

 

No engines in Maui junkyards.
Yeah, that's what mech said, compression issue.
Oh well...

 

well, bad compression can be due to a couple things.

1) worn rings, cylinder walls == pretty much junk the motor unless you cna rebuild it yourself

2) cracked piston crown (see 1)

3) valve problem (burned valve, valve thats not closing completely, eroded valve seat, etc) == new (used) head

a new (used) head could be shipped from the mainline for not too unreasonable expense. and replacing the head isn't an unreasonable amount of labor. I'm in California and got a B230FT head from a guy in Texas for like $200 including UPS blue shipping. The 16V heads are rarer and probably more expensive, however.

 

Ok, thanks for laying that all out. That's why this forum rocks.

 

ouch. did some random googling. volvo b234f heads apparently are prized by some racers, they fit on a ford ranger 4 banger and give way more power or something. eek, so prices are premium. might be easier to find a non-16V B230F complete engine

 

Yeah, I'm thinking we're just gonna drive it until it kicks over and start fresh.