Some of you know I just did a lot of work on my Tracker.

The truck has been running great for the week and a half since I finished it.

Well, I went out this morning to remove the throttle body spacer I made, that went without incident (I think), and while I was at it    I thought I'd check my compression (a big reason for all the work I had done).

Compression was fine at 160, 145, 150, 155.

BUT, I noticed while I was checking compression on the #2 plug that the tach stopped showing RPM    It was OK on #1 (maybe reading a little slow), but on #2 and the rest it stayed at ZERO.

So, I finished installing the plugs, buttoned her up, tried to start and nothing    I have fuel coming out of the injector nicely, I checked spark at the #1 plug and that was fine, but, I still show ZERO RPM when it's cranking.

I'm gonna go put on an old coil and old plugs, but I don't have much hope; I think it's gotta be something electrical.

EDIT:  Actually, I think I'll put the diagnostic fuse in first and see if anything shows up.

Oh, I checked the coil fuse in the fuse box and it was fine.

I'm stumped AND VERY, VERY FRUSTRATED  

SOunds electrical, I would look and see if anything got bumped loose or not reconnected. Then go back to basics spark? you have fuel, timing, check distributer for tracking etc, and good battery. Good luck hope its an easy one. JL

Well,  I just:

1.  Checked all of the fuses I could find in the cab and the engine compartment -- All fine.

2.  Replaced all of the plugs and the coil with some old stuff I had -- No difference.

3.  Cleaned the rotor and contacts under the dist cap -- No difference.

4.  Zero'd up the timing marks and the rotor points to #1  -- As it should.

5.  Checked all of the wires near the throttle body -- All look OK (I guess except the one that has a problem and I'm missing    )

6.  Tried to start it to see if the computer could capture a code, plugged in the diagnostic fuse, got a Code 12 -- Normal.

7.  Disconnected the battery for 15 minutes to let the computer reset -- No difference.

8.  Check the wires coming off of the distributor (where I would guess the RPMs are captured) -- Didn't see any problems.

:-/  I'M FREAKIN' STUMPED   :-/

I'm gonna read the Haynes and FSM to see if I can find out what feeds the tachometer and tells it the engine is turning (since that connection seems to be broken).

I'm really hoping someone has seen this before and can help.  I'm starting to think it may be the computer or something  

DO you have spark to the plugs?

DO you have spark to the plugs?

Yup.

7.  Disconnected the battery for 15 minutes to let the computer reset -- No difference.

Read the manual and disconnected the dome/tail fuse for 20 seconds to clear the ECM's long term memory.

Checked some of the problems described in the FSM (what a disorganized PITB that thing can be) and everything checked out OK; as far as I can tell, that is, I HATE electronics.

Y1 (#1 on the yellow connector) is what I understand to be the signal from the dist for tach.  It's supposed to be "on" (I guess that means 12v) with the ignition at "On" -- it was.  It's supposed to alternate On/Off when the engine is cranking; it averaged 6v on my multi-meter then, so I guess that's the same as 12v for On and 0v for off  

Anyway, I'm about ready to call it quits with this thing -- it's just too frustrating and too much time lately  

So it starts and runs, but the tach
is not working, right ?

So it starts and runs, but the tach
is not working, right ?

I'd be thrilled if that were the case.

No, I'm afraid it doesn't start.

It has spark to the plugs, it has fuel.

After messing with it and doing what little electronic troubleshooting I can figure out, I think it may be the ECU.

I can't imagine what I could have knocked loose.

It was running great and I killed it  

If it has spark and fuel (in the chamber), it should go boom.

sure about spark (at the right time)
sure about fuel (in the chamber)

Don't mean to sound like an ass, but I've heard of people saying "I checked the wiring", which meant they looked at it and nothing was melted together.

If it has spark and fuel (in the chamber), it should go boom.

sure about spark (at the right time)
sure about fuel (in the chamber)

Don't mean to sound like an ass, but I've heard of people saying "I checked the wiring", which meant they looked at it and nothing was melted together.

I agree with the "boom" statement.  It seems like it would have to run.

If the computer were bad, would I not have spark?

I didn't try the timing light while cranking it; I may give that a shot, and I only checked #1 for spark.  But, I did check the timing marks and they lined up when #1 was at TDC.

The very puzzling thing is the tach.  I don't understand why it doesn't know that the engine is turning.

No help on this  :-/

The big question is:  Has anyone ever had their tach stop working?  Is there a common reason for the tach to show 0 RPM while cranking?

I don;t have my service manual handy but from what I recall ...

The tach is fed from the inducer? (not the coil)? I also recall that the inducer has some wimpy 18 guage wire running to ground (on the firewall?). If the ground has gone bad, you could get your symptoms.

As for testing spark, the ONLY reliable means is with the plugs in, under compression, and using a timing light. Pulling a plug wire and seeing a spark to ground doesn't show that the PLUG is actually firing. If the spark is weak, you might see a wire spark, but if the timing light inducer can't pick up spark from the wire (with plugs in under compression), then you know you really aren't getting spark.

Other items to check ...
cap/rotor (carbon traces?, hair?)
is the wire to the distributor getting consitant fire (using timing light with plugs in)?

You might have gone down this road already, but sometimes the simple crap get's your hair pulled out ... (i.e. what's the fuel guage read:) )

Rob

on my tracker and someone i know when the computr was bad we both had spark and both had fuel getting to the eingine, may be the computer?

No, if you have spark and fuel the
engine would start

no, it wouldnt and it didnt, not on mine and not on a freind of mine,