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89 NOT starting Replaced CPS TPS....

againstherwill

NAXJA Forum User
Location
Indianapolis
Okay Heres the Scoop. I have an 89 il4.0. Been sitting for two years while I got stuff together. Any Prior to it dying 2 years ago it ran. Was running down the highway and all of the sudden it started loosing power. Barely Got to dealer. Dealer wouldn't diagnose it because it was 89. NP I bought a 2001. FF to This week. Decided I wanted to get it going.

Read all sorts of not starting posts. Here is what I have replaced with NEW

Fuel Pump
Fuel Filter (no Flow
CPS (Wires Burned throug)
TPS (too many threads blaming this so replaced)
EGR (Was definitely bad)
Fuel Pressure Regulator (Diaphram leaked)
Distributor Cap (deposits on
Distributor Roter (deposits on head)
Spark Plugs (old)

NOT Replaced and why
Spark Plug wires, meter tested all Good.

Here is the issue
NOT STARTING
Starter fires and Turns but engine won't fire
I Have fuel and pressure at the check valve
I have Spark at the plug (checked by Grounding plug and Firing Lots of Spark)
if I spray starter fluid down the TBI It runs while there is fluid
I have checked wiring from harness to seems good.

Help!

Any suggestions?
 
Fuel injectors? They're probably toast. I know that on my 89 they died out in rapid succession until I had all of them replaced. You'd still be getting pressure at the check valve, but not any in the combustion chamber. Take the old injectors out and take a look at em.
 
Would you get pressure at the rail if this were the case. because at the check valve I get good pressure. Also I pulled the fuel rail when I replaced the pressure regulator and made sure the injectors were not plugged. Any one have a way to test an injector?
 
Okay sorry for the stupid here but "PowerLatch relay"?

Any suggestion on the proper fitment of TPS or testing? Not to be stupid but I would love to get this running today.
 
Might as well check the ground for the injectors, it actually ends up as the same ground, as for the ECU, but goes through a couple of splices. Then through the C-101 connector and finally ends up at the dipstick holder. More than once I've seen fatigued wires at the bend at the fire wall, in the fuel rail harness. A single thread of wire will check OK for continuity, but won't pass enough juice to do you any good.
While your in the area, take a good look at the harness that goes from the front of the fuel rail down the front of the motor and to the O2 sensor, knock sensor and engine temp. sensor. This harness also often fries on the exhaust manifold.
 
Okay I adjusted the TPS got 4.8 on the in and 4.0 So that should do that.
I will Check the ground as I did replace the the rear main seal and the oil pan gasket, could have nocked it loose there. I will also the leads to the injectors.
Thax
 
They did away with the C-101 connector on the 89? But there is still, I believe, a grey sensor connector near the booster, or I'm getting my years confused again.
 
againstherwill said:
Okay I adjusted the TPS got 4.8 on the in and 4.0 So that should do that.
I will Check the ground as I did replace the the rear main seal and the oil pan gasket, could have nocked it loose there. I will also the leads to the injectors.
Thax
What? did you get at closed throttle? That should be around .57 - .95 volts
4 volts at closed throttle would turn the injectors off.
 
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The half of the TPS closest to the TB, is the one you need to check, in this situation. Check it the same way as recommended for a stick shift. If you back pin the connector, I always check both sides of the connector. The ECU half of the TPS works backwards from the transmission half, it starts at a low voltage and when the throttle is opened the voltage increases. Supply voltage is typically 4.65 volts and the out voltage is typically .6-.65 volts (the ideal is.08 volts). But the recommended adjustment is at the tranny half of the TPS, so the ECU half seldom has the ideal value, but seems pretty forgiving.
 
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Okay visually checked the harness down the fuel rail and the to front and around and no frying there And all still wrapped tight but that doesn't mean something on the inside isn't bad but that will have to wait. It has to be a wire though. Unless could the map cause not starting, I haven't replaced that yet?
 
againstherwill said:
Okay visually checked the harness down the fuel rail and the to front and around and no frying there And all still wrapped tight but that doesn't mean something on the inside isn't bad but that will have to wait. It has to be a wire though. Unless could the map cause not starting, I haven't replaced that yet?
You can test that also just like the tps. A to C 4.5-5 vdc(input) A to b 4.5-5 vdc(output)
 
Just thinking out loud, but if the cam position sensor went, it could have been running but very poorly (like what you described). The write up's I've read on the cam position sensor are kind of contradictory. One said something like the ECU uses a best guess, when deciding when to fire the injectors when the sensor is bad, another said it defaults to the last value. If it's been sitting for years, there is no last value.
May be a waste of time, but a cam position sensor test, doesn't take long and will probably eventually have to be done anyway.
I had one XJ that started running really poorly and eventually died, it turned out to be the O2 sensor cable burnt onto the exhaust manifold, behind the power steering pump. I most always look there now and have often found partially melted harness. Something else that may not be your problem, but has to be checked anyway.
If some of the more likely stuff doesn't pan out, I can give you a few tests for the unlikely.
There are actually two separate circuits to the ECU, start and run. A good quick test for this circuit is to test the pump end of the ballast resistor, with the key in run (usually around 9 volts) then again with the solenoid wire pulled at the starter relay and the key in the start position, the voltage should be near battery voltage.
The TPS is two halves, one half for the TCU and one half for the ECU. Testing the input voltages for the TCU half, doesn't tell you anything about the ECU inputs.
 
just tested the map and got 4.8 on A & C and 4.4 on A & B.

I looked at the harness behind the ps and ther are no visible problems
anyone got a test for volts at the injectors?
 
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