2.3L tach reads too low
 

I have the 2.3l dual plug engine in my 91 ranger. The tach works, but it reads way too low, like 200-600 rpm at idle and never above 2000 when driving. Ive swapped the tach with a different one and the problem didn't change. I followed the tan/yellow wire (supposedly the signal wire) out, across the engine compartment, and back in to the computer. It looked fine. The truck runs perfectly, so what could be causing this? The check engine light is on because of codes 18-Erratic TACH signal, and 88- IDM, DPI, or Spout circuit fault. Any ideas?

i did the same thing as you to my 94 2.3l and i had the same problem. I believe it is because the tach only came in the v6 rangers so it wont read right it will read too low like you said. I asked around and read the fourms and no one could tell me how to fix it to read right. I now have a 5.0l in the truck and it reads too high about 500 rpms and goes over red line. sorry i cant help. im still in the same boat. lol i need help too.

I had a similar situation when I swapped out my 92 cluster with a 93 that came with a tach. I found an interesting article "Installing a 1992 Explorer instrument cluster into a 1993 Ranger". Since I was reversing this procedure...changing an 1993 Explorer Instrument Cluster into my 1992 2.3L 4cyl. I had to reverse the procedure. In order to make the tach work from the 6cyl Explorer, I followed the writer's comments and had to remove the Blk/Yel wire from Pin #9 and tape it out of the way. Pin #9 was found on the vertical wiring cluster behind the instrument panel.

Just a note...I wound up swapping the entire instrument panel and pulled the 2 plugs leaving 6" of wiring attached. Through this article, I replaced the wiring (working backwards since I was going from a 6cyl to a 4cyl OBD1).

Good Luck

Re: 2.3L tach reads too low
 

Why does/did my 1994 have one in it with a 2.3L?

Re: 2.3L tach reads too low
 

I know this thread is extremely old, but to answer this, any Ford Ranger had an option for a tach... at least I'd be surprised to find out otherwise. As to my original problem, I figured out long ago that one of my two coil packs was burned out which was causing the half signal problem.

Re: 2.3L tach reads too low
 

Good info! Thanks for coming back and posting your solution!

Re: 2.3L tach reads too low
 

Replaced my tach yesterday with a NOS piece. It was alot easier than perceived.

Re: 2.3L tach reads too low
 

When I installed a cluster from a '96 Explorer into my '95 Ranger I found that the Tach Select wire (4 or 6 cylinder) and the MIL wire (Check Engine Light) were reversed in the plug going to the cluster. What happens is that every time I get a check engine light the Tach would drop 33% but I would not see the check engine light come on! Since I have an SCT Excalibrator II I just leave it plugged in and clear the codes whenever the tach drops. Looking that the diagrams for the truck and explorer I noticed that a 6 cylinder explorer would have 12 volts on the tach select pin and a 4 cylinder would not. The way to see if this is your problem is to look for a check engine light when you are starting the truck. If you don't get one it is a pretty good indication that the wires are switched.

Re: 2.3L tach reads too low
 

i have same problem. how did you test which coil pack was bad? i am sure this is what is wrong with mine. thanks with any help.

Re: 2.3L tach reads too low
 

I just unplugged one coil pack, and attempted to start the truck. In my situation it didn't start on the first try, so I knew that the coil pack I unplugged was the culprit. If you unplug one, and it still starts, plug it back in and try unplugging the other one. If it doesn't start, then you will know that the one that is currently plugged in is bad. Simple process of elimination, and you will have your answer :). Hope this helps you out.

Re: 2.3L tach reads too low
 

Was the one that was bad happen to be the coil pack for the exhaust side?

I think you may have been lucky there because from what I've heard/read is that the exhaust side plugs don't really run the engine but spark on the exhaust stroke to eliminate unburned fuel.

Re: 2.3L tach reads too low
 

Actually it is the opposite. The plugs on the exhaust side are the primary spark, and the ones on the intake side (which were burnt out on mine) are for emissions. These plugs also give the 2.3l a little horsepower boost compared to the older 2.3l with only 1 set of spark plugs. I definitely felt a difference, especially when I decided to replace the other pack that still worked. Now both are new, and the truck seems to have a significant increase in power.

Re: 2.3L tach reads too low
 

well pulled plug on exhaust side it would not start tried 3 times,, plugged back in and it started,,, so the intake side coil pack must be what is bad on mine. boy it looks like job to get to and replace. thanks so far guys, will let yall know what happens

Re: 2.3L tach reads too low
 

Before buying a new one, bring the intake coil pack into your local auto parts store (like autozone) and have it tested. I know places around here will test them.


No sense in blowing the money if it works fine.

Re: 2.3L tach reads too low
 

Well this sounds exactly like my situation was. Yes, that coil pack is a pain to replace. I had to unbolt the alternator and power steering pump, and was able to swing them out of the way. Even when you get to the coil pack, the little bolts on mine were pretty much rusted in, and I broke one of them, so be careful. To this day I only have 3 bolts holding that pack in because it was too difficult to try and get a drill in there to drill out the old bolt. Might be wise to get some penetrating oil on them and let it sit for a while.