1989 caravan 2.5 turbo runs rough
#1
11-08-2007, 07:11 PM
1989 caravan 2.5 turbo runs rough
I have a 1989 caravan 2.5 turbo I picked up from a friend
the van is like new not a spot of rust on it & only 120000 KM
the only problems I am havingare that it runs rough when I first start it this problem is worse in colder weather but if I run it for 30 to 45 seconds @ 2000 rpms it will smooth out & run fine.
the other problem is when starting a warm engine it is hard to start.
it will catch right away but stall once, then I have to crank it for 10 to 15 seconds to kind of wind up the rpms then it will start & run fine.
I changed the plugs, wires, cap & rotor but it made no difference.
the van has been in storage for 3 years so I ran some emission system cleaner through it then took it for its emission test & it passed fine.
however now that the weather is turning colder this rough starting is becomming more of a problem.
does anyone have any ideas as to what could be causing this problem ?
Thanks in advance for any help, Joe
the van is like new not a spot of rust on it & only 120000 KM
the only problems I am havingare that it runs rough when I first start it this problem is worse in colder weather but if I run it for 30 to 45 seconds @ 2000 rpms it will smooth out & run fine.
the other problem is when starting a warm engine it is hard to start.
it will catch right away but stall once, then I have to crank it for 10 to 15 seconds to kind of wind up the rpms then it will start & run fine.
I changed the plugs, wires, cap & rotor but it made no difference.
the van has been in storage for 3 years so I ran some emission system cleaner through it then took it for its emission test & it passed fine.
however now that the weather is turning colder this rough starting is becomming more of a problem.
does anyone have any ideas as to what could be causing this problem ?
Thanks in advance for any help, Joe
#2
11-08-2007, 07:48 PM
RE: 1989 caravan 2.5 turbo runs rough
Coolant temperature sensor. Probably thinks the engine is warmer than ambient but cooler than operating temperature. This will cause it to be too lean on a cold start and too rich for a hot start. Once the 02 sensors heat up andstart sending signal, the computer no longer uses the CTS for fuel metering.
If you have a DVOM, I can post hte resistance value chart so you can test the CTS. Otherwise, they're cheap enough to guess.
If you have a DVOM, I can post hte resistance value chart so you can test the CTS. Otherwise, they're cheap enough to guess.
#3
11-09-2007, 05:51 AM
#4
11-10-2007, 02:45 PM
#5
11-10-2007, 06:30 PM
RE: 1989 caravan 2.5 turbo runs rough
Yes,I think i might be of some help.
As an engine gets a few,well a lot,of miles on her the intake system gets dirty.This "dirt" comes from PCV fumes drawn out of the crankcase and fuel deposits.These deposits can be cleaned out of the intake with a couple of cans of spray carb cleaner.Warm the engine to operating temperature,remove the hose going into the throttle body and spray away.There will be lots of white smoke from the exhaust but don't worry,that's just the cleaner doing it's job.
The biggest problem with cold starts is the carbon and varnish deposits on the backs of the intake valves.These soak up part of the fuel and hold it until the engine starts to warm up like a sponge.When the valves get hot enough,they boil the unburned fuel off the backs of the valves and it gets burned in the combustion chambers normally.The large amounts of carb cleaner you are about to shoot into your engine will clean off part of this gom.
Short trips of less than twenty miles is the cause of this build up due to the gasoline left in the intake and on the injector tips when the engine is shut down.The gas dries on the injectors and valves and leaves a little gasoline stain.If the engine isn't run long enough for the detergents in the gas to remove the original deposit,they build up into a growing problem.The engine in your van probably has a throttle body injector instead of individual cylinder injectors but there could still be a problem starting there.Again,a good dose of carb cleaner will go a long way to clean off any deposits.
The PCV system also contributes to this by pulling crankcase gasses into the intake for disposal puposes.these are particularly dirty because they consist of oil vapors,unburned gasoline,water vapor,acid vapor,and exhaust blow-by.You can see how something like that would tend to clog parts of the intake system.
Fuel system cleaners can be added to the fuel tank.I personally mix them very strong at a one can for every three gallons of gas.I know that's a lot more than recommended but unless you want to be adding cleaner for the rest of your life,that's what it takes to clean a really dirty engine.One major warning!!! This much fuel system cleaner WILL decrease the octane rating of the gasoline so either go up a grade or two or listen for detonation when accelerating.I have done this in my Mustang GT and it hasn't killed it so I figure your van will be OK.
The coolant sensor can also cause the problems you're having so I agree with the above posters on their course of action,but spraying carb cleaner into the engine and covering the entire neighborhood in white smoke is just too good to pass up.
As an engine gets a few,well a lot,of miles on her the intake system gets dirty.This "dirt" comes from PCV fumes drawn out of the crankcase and fuel deposits.These deposits can be cleaned out of the intake with a couple of cans of spray carb cleaner.Warm the engine to operating temperature,remove the hose going into the throttle body and spray away.There will be lots of white smoke from the exhaust but don't worry,that's just the cleaner doing it's job.
The biggest problem with cold starts is the carbon and varnish deposits on the backs of the intake valves.These soak up part of the fuel and hold it until the engine starts to warm up like a sponge.When the valves get hot enough,they boil the unburned fuel off the backs of the valves and it gets burned in the combustion chambers normally.The large amounts of carb cleaner you are about to shoot into your engine will clean off part of this gom.
Short trips of less than twenty miles is the cause of this build up due to the gasoline left in the intake and on the injector tips when the engine is shut down.The gas dries on the injectors and valves and leaves a little gasoline stain.If the engine isn't run long enough for the detergents in the gas to remove the original deposit,they build up into a growing problem.The engine in your van probably has a throttle body injector instead of individual cylinder injectors but there could still be a problem starting there.Again,a good dose of carb cleaner will go a long way to clean off any deposits.
The PCV system also contributes to this by pulling crankcase gasses into the intake for disposal puposes.these are particularly dirty because they consist of oil vapors,unburned gasoline,water vapor,acid vapor,and exhaust blow-by.You can see how something like that would tend to clog parts of the intake system.
Fuel system cleaners can be added to the fuel tank.I personally mix them very strong at a one can for every three gallons of gas.I know that's a lot more than recommended but unless you want to be adding cleaner for the rest of your life,that's what it takes to clean a really dirty engine.One major warning!!! This much fuel system cleaner WILL decrease the octane rating of the gasoline so either go up a grade or two or listen for detonation when accelerating.I have done this in my Mustang GT and it hasn't killed it so I figure your van will be OK.
The coolant sensor can also cause the problems you're having so I agree with the above posters on their course of action,but spraying carb cleaner into the engine and covering the entire neighborhood in white smoke is just too good to pass up.
#6
11-12-2007, 11:13 AM
RE: 1989 caravan 2.5 turbo runs rough
this van has port fuel injection so I will try adding consentrated injector cleaner for a while & see if that helps, as I can see black carbon build up in the exhaust pipe that has been getting cleaner since Ive been driving it.
This van belonged to an old man who always drove the speed limit & mostly local short trips driven with one long trip from Ontario Canada to Florida & back every year.
This van belonged to an old man who always drove the speed limit & mostly local short trips driven with one long trip from Ontario Canada to Florida & back every year.
