My 92 ranger has been giving me issues lately. I was able to work some out and now it idles nicely.

The issue I'm having is that when I put it in 1st gear or reverse the car pretty much stalls unless i keep the clutch pressed in about mid to 3/4 of way while feathering the gas. On other vehicles i've been able to move the vehicle with just clutch play.

Once the vehicle is backed up and going into first is the same issue to where there's no power until you get to about 10mph.

any help would be appreciated.

 

4cyl should be idling at 750rpm, much lower and it will not have any power, will also vibrate alot, lol, 4cyl's only fire every 180deg of crank rotation

On cold start idle should be 1,000rpm, this is Choke Mode, rich fuel mix and high idle
Does it do this?

If not then ECT sensor could be the issue, it tells computer coolant temp so it will use Choke Mode on cold start
Also IAC Valve is used by computer to set the higher idle when cold
Fuel injection can't use an idle screw or choke plate because there are No "JETS", so computer has to run the Choke which all gasoline engines need on cold start

 

I'll look into this and get back with you Ron!

 

Ok so I installed a Tach on the vehicle since it didn't come with one from the factory. I let it idle for 15 minutes and the RPM showed 900-1000 RPM the whole time (temp gauge never moved). is the a way to check that the ECT sensor is working correctly?

it's idling very bad with lots of vibration, i unplugged the IAC with the engine running and it did not change the idle. the vehicle should stall with the IAC disconnected correct?

 

Yes, RPMs should drop below 600rpms when you unplug IAC Valve while engine is running, and engine can stall as well

On warmed up engine if RPMs do not drop then you most likely have a vacuum leak, which will also cause rough idle
Leave IAC Valve unplugged, on running engine, and then disconnect one vacuum hose at a time on intake manifold, and plug the port with your finger
Start with Power brake booster vacuum hose and then PCV valve hose, then move on to smaller hoses
When RPMs drop or engine stalls you found the hose/device with the leak

If IAC Valve was the issue your idle would be high but NOT rough, so its not an IAC Valve issue

 

so it seems that break booster and PVC are fine.

I did find the following hoses that were disconnected and couldn’t find a place for em

I’ll buy a vacuum gauge tomorrow to check what the current vacuum is, is there a number I’m trying to stay between?

 

At sea level to 1,000ft above sea level, gasoline engines should be 18" to 21" of vacuum, and steady at idle

 

looks like it’s 25” of vacuum.



Needle jumps a bit, you can see how shaky the engine is in the background

 

Looks like restricted air flow into the engine
Remove air filter and see what it shows, leave top off air cleaner box

Could be the gauge if its new
If possible test gauge on another engine, any engine should show 18 to 21" its an atmospheric thing not engine specific, 4cyl to V12 should have same vacuum range

 

so I think the previous gauge was bad because it would never go to zero. Bought a new one and still not at zero but close enough?




so now it looks like it’s hovering in the 15 in Hg area.

 

I won't trust the vacuum reading since it would seem both gauges are bad.

Regardless,

I went ahead and did a compression test on a cold engine.

• Cylinder 1 - 120PSI
• Cylinder 2 - 110PSI
• Cylinder 3 - 130PSI
• Cylinder 4 - 125PSI

As far as compression they all seem to be within 15% of each other so it should not be misfiring.

Also did a leakdown test.

• Cylinder 1 - 30%
• Cylinder 2 - 15-20%
• Cylinder 3 - 10%
• Cylinder 4 - 10%

Something I noticed while performing the test is that the coolant would trickle out of the radiator neck for cylinders 1-2. From the research done I believe its a blown head gasket since cylinder compression would have no effect on coolant unless the gasket is bad.


I will be testing the DIS system next.

 

Well the cylinder head was bad. Had recessed valves and the machine shop said the head was cracked. Looking at purchasing a reman head, do i have to stick with a 89-94 cylinder head or could I use one from 95-97s? @RonD