1998 fuel system sohc

[tom.h]

Hi all
Just a quickie. I have a 1998 SOHC . could someone please tell me. is this single point injection or multi? Reason for asking, idles great misfire under load, could be plugs or injectors or leads. Car has been stood for 2 years. Also the switch inside small locker in the boot area. says on/off is this fir the self leveling?

Regards

Tom

 

[donalds]

Check your fuel pressure

 

[Mbrooks420]

It’s multipoint. Probably Have a tank full of crust. Yes, that’d the air ride. Doubtful it still works.

 

[tom.h]

Hi It is running just missing between 1500 and 2000 rpm. Have just treated with Redline Sl-1. will see how things go.. Air ride pump is working . but not sure if system is. needed to know about injection system . as single point would be less likely to cause misfire. whereas multi point could be blocked injector?
Thanks for quick replies
will let you know how i get on.

Regards

Tom

 

[tom.h]

Check your fuel pressure

Hi Donalds.
Fuel pressure ok.

Regards

Tom

 

[J_C]

Hook up a scan tool, check for OBD2 codes set and live data including fuel trims.

What is your fuel pressure in the misfire state? Did Explorers in the UK have the return fuel system through '98 like they do in the US or already switch to a returnless system? The returnless has a higher ~60+ PSI. The return system can be seen by looking at the end of the fuel rail, where it will have a fuel line going back to the tank in addition to a vac line for the pressure regulator. Returnless has the vac line but not fuel line back to tank.

You might want to pull spark plugs and examine to find misfiring cylinder, it is not good for the catalytic converter to run long with unburnt fuel dumping into it. Test for spark on suspect cylinders, test for power at those injectors and then pull fuel rail if nothing else found yet.

I'd also check the battery, if sitting drained for a couple years, might not be taking/holding sufficient charge so weak spark.

 

[tom.h]

Hook up a scan tool, check for OBD2 codes set and live data including fuel trims.

What is your fuel pressure in the misfire state? Did Explorers in the UK have the return fuel system through '98 like they do in the US or already switch to a returnless system? The returnless has a higher ~60+ PSI. The return system can be seen by looking at the end of the fuel rail, where it will have a fuel line going back to the tank in addition to a vac line for the pressure regulator. Returnless has the vac line but not fuel line back to tank.

You might want to pull spark plugs and examine to find misfiring cylinder, it is not good for the catalytic converter to run long with unburnt fuel dumping into it. Test for spark on suspect cylinders, test for power at those injectors and then pull fuel rail if nothing else found yet.

I'd also check the battery, if sitting drained for a couple years, might not be taking/holding sufficient charge so weak spark.

I will have to speak to a friend as have no scanner. Battery brand new. Old one knackered after standing so long.
I will let you know results of scan as soon as I can.

Thanks for reply

Tom

 

[Mbrooks420]

A battery won’t contribute to weak spark.

 

[J_C]

^ Yes it will. Even if a vehicle can run on alternator alone (not a good idea due to electronics and peak voltages produced), a bad battery can pull the voltage down and ignition coils are a multiplier of that voltage based on # of coil wraps.

It's more common with well worn spark plugs... we don't know the vehicle history.

 

[Mbrooks420]

No. If your battery starts the car by itself it’s not going to effect the spark. Once started all the juice comes out of the alternator essentially because it’s voltage is higher.

I’m aware of what a transformer is, and how they work.

 

[J_C]

^ I have observed this with mine for years, often making short trips but then when I drove it more than day prior, runs significantly better, as it does if I put a battery charger on it beforehand, though never bad enough to have misfire codes set.

If your battery is low it is pulling down the alternator voltage, so stating all juice comes from alternator, does not change that it's less voltage.

 

[Mbrooks420]

The voltage increases until the regulator/rectifier portion says so. It’s not like it just puts out X amount of voltage, and that’s that.

Unless you have an alternator(or a shorted battery cell) issue your battery should be at 100% charge before your motor is even close to warm. Several short trips won’t drain your battery.

 

[J_C]

^ I've observed this for several years, both before and after new alternator and batteries. Less so after plugs and wires (I was getting misfires with the old plugs and wires but only as above, when battery was drained some) but still noticeable. It doesn't run bad, just not as good. Yes it is before the engine is warm, many of my short trips are less than 5 minutes, running up to the store at night so extra drain from headlights, low RPM on alternator as much of the distance is getting out of the neighborhood with low speed limits.

You are missing the point here. "Battery should be at 100% charge" only applies if there isn't anything wrong with the battery. Short trips are only one reason a battery can be at less than full charge voltage. Another is sitting at a discharged state for two years that ruins a lead acid battery.

 

[Mbrooks420]

I’m aware that it should be at 100% charge if nothing is wrong, since that’s exactly what I stated in the post above.

 

[CDW6212R]

With the truck parked for so long, I;d suspect the fuel being too old. I've had that issue more than once, the engine will run but with degraded performance and some amount of misfiring. I had one that got worse over a couple of weeks until the old 1991 system coded as a multiple misfire on about five cylinders. That one the gas messed up the injectors, and I had to replace them all.

I'd start with the fuel filter, even if you just did it before the issue. You want to see the fuel in person, pouring out of the filter. If the engine was known to run fine before not running for so long, the fuel is the easiest best bet. Check all of the other easy stuff first of course before yanking the tank or injectors. Check the plugs and those wires carefully, plus all of the main engine connectors if you can. Look for any wiring damage or loose connections, or even vacuum hoses, cracks etc.

 

[tom.h]

With the truck parked for so long, I;d suspect the fuel being too old. I've had that issue more than once, the engine will run but with degraded performance and some amount of misfiring. I had one that got worse over a couple of weeks until the old 1991 system coded as a multiple misfire on about five cylinders. That one the gas messed up the injectors, and I had to replace them all.

I'd start with the fuel filter, even if you just did it before the issue. You want to see the fuel in person, pouring out of the filter. If the engine was known to run fine before not running for so long, the fuel is the easiest best bet. Check all of the other easy stuff first of course before yanking the tank or injectors. Check the plugs and those wires carefully, plus all of the main engine connectors if you can. Look for any wiring damage or loose connections, or even vacuum hoses, cracks etc.

Hi
The truck was running bad before . Hunting. I have replaced inlet manifold gasket. It now runs better. I have also added 3 gallons of fuel and red ? Fuel additive. Also oil and filter change with flushing agent. Running better, idle a little high 1100/1200 smoother revs. Just lumpy between 1500/2000. At oil change, lots of crap . Seems to be non metallic. Suspect its carbon.

 

[CDW6212R]

The oil being dirty won't notably affect running, but that is another concern, a major one for the SOHC 4.0 engine. Work on the engine running for sure now, but also aim to get the oil much cleaner. The oil should be completely clean whether new or old. Use synthetic oil or your choice, and change ti more often until you find a point that keeps the oil looking very clean. That's the life or death of the timing chain system in those, the tensioners especially. The SOHC must have super clean oil all of the time.

It sounds like before the stored period, it needed some care, I'd clean the IAC solenoid now. That's very easy and quick, that has full control of the idle, and any sticking of it due to debris etc, will mess with the idle smoothness.

Depending on how much fuel was in it and stored for a long time, it may need to be drained or pumped out. If you see it showing as much off color, not very clear, it might be time(or too late) to discard that gas. I much prefer real gas for any vehicle I don't drive much. Do you have access to any fuel which has no alcohol in it? That's what makes gasoline go bad now, the alcohol they force us to use. Real gasoline used to last for countless years and still work "okay." Now the junk alcohol fuel can go bad in a year, and drastically hurt the engine running, or foul injectors etc.

 

[tom.h]

The oil being dirty won't notably affect running, but that is another concern, a major one for the SOHC 4.0 engine. Work on the engine running for sure now, but also aim to get the oil much cleaner. The oil should be completely clean whether new or old. Use synthetic oil or your choice, and change ti more often until you find a point that keeps the oil looking very clean. That's the life or death of the timing chain system in those, the tensioners especially. The SOHC must have super clean oil all of the time.

It sounds like before the stored period, it needed some care, I'd clean the IAC solenoid now. That's very easy and quick, that has full control of the idle, and any sticking of it due to debris etc, will mess with the idle smoothness.

Depending on how much fuel was in it and stored for a long time, it may need to be drained or pumped out. If you see it showing as much off color, not very clear, it might be time(or too late) to discard that gas. I much prefer real gas for any vehicle I don't drive much. Do you have access to any fuel which has no alcohol in it? That's what makes gasoline go bad now, the alcohol they force us to use. Real gasoline used to last for countless years and still work "okay." Now the junk alcohol fuel can go bad in a year, and drastically hurt the engine running, or foul injectors etc.

Hi
I have had the top inlet manifold off and cleaned and replaced gasket also cleaned the iac valve, air flow sensor, air temperature sensor, butterfly valve. In fact all the top end. Think my problems can only be caused by plugs or leads. Have put new fuel in with an injector cleaner. Think I will leave for a while, run now and again, as car is off the road at the moment.
Thanks for reply, much appreciated.
Tom