ogune

My jeep cherokee 87 wont rev more thand 1.500 and the fire cut and as no power, idle is ok and nutrale is ok
Change cap,rooter,wiereplug and plug coll comprecion is ok injector clean with pluse clanner at home voltage is ok grund is ok pessure fuel is ok gaz pump is ok and filter is ok

RatchetMaster10

From the sounds of it I would check for a plugged converter. Probably the easiest way to check is remove the o2 sensor in front of the converter and see if your able to rev it higher or undo the exhaust at the converter and try that. Let me know if ya do and what results you get.

ogune

i dont enderstan what do you mean ? but my exhaust is new and open only one sensor and neare manafold

fishtaconc

Say huh?

DFlintstone

Maybe he needs to go somewhere where he can put out a better signal?


pblty wtten By Cruiser ;

Renix CPS Testing and Adjusting
　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

ogune

ok il try to change the cps but if tha thoes not work then what could it be somting elesse ?

DFlintstone

NO! lol. I thought you might just check it since really, it can be pretty easy. Really I'm clueless, (would have mentioned a restricted exhaust). Cleaning up the ECU, TCU, and sensor grounds might be a start, is really all I can suggest. maybe the tps? Don't know.

cruiser54

TEST IT!! You've got the instructions. This is a process of elimination requiring some effort on your part since you're there and we're not.

tjwalker

Fuel delivery and electrical fuel control needs to be ruled in or out early in the process. (assuming you're certain the cat isn't clogged).

1. Test fuel pressure with a GAUGE. No shortcuts. For an 87, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi. Be sure that the vacuum line to the FPR is pulling good vacuum.

2. Test and adjust your "throttle position sensor". More on that below.
-------------------------------------------------

RENIX TPS ADJUSTMENT

Before attempting to adjust your TPS be sure the throttle body has been recently cleaned.
It's especially important that the edges of the throttle butterfly are free of any carbon build-up.

IMPORTANT NOTE: Using one lead of your ohmmeter, probe the B terminal of the flat 3 wire connector
of the TPS . The letters are embossed on the connector itself.
Touch the other lead of your meter to the negative battery post.
If you see more than 1 ohm of resistance some modifications to the sensor ground harness will be
necessary. The harness repair must be performed before proceeding.
I can provide an instruction sheet for that if needed.

MANUAL TRANSMISSION:

RENIX manual transmission equipped XJs have a three-wire TPS mounted on the throttle body.
This manual transmission vehicle TPS provides data input to the ECU. The manual transmission
TPS has three wires in the connector and they're clearly embossed with the letters A,B, and C.

Wire "A" is positive.
Wire "B" is ground.

Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors..
Note the voltage reading--this is your REFERENCE voltage.

Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your
OUTPUT voltage.
Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For
example: 4.82 volts X .17=.82 volts. Adjust the TPS until you have achieved this percentage. If
you can't achieve the correct output voltage replace the TPS and start over.

AUTOMATIC TRANSMISSION:

RENIX automatic transmission equipped XJs have a TPS with two connectors. There is a three-
wire connector, same as the manual transmission vehicles have, and it is tested the same as the
manual transmission equipped vehicles--FOR ENGINE MANAGEMENT RELATED ISSUES.

However, the automatic TPS also has a four-wire connector clearly embossed with the letters
A,B,C, and D.. For the automatic transmission equipped vehicles the four-wire connector
provides data to the TCU.

Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your
REFERENCE voltage.

Back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT
voltage. Your OUTPUT voltage needs to be eighty-three percent of your REFERENCE voltage.
For example 4.8 volts X .83=3.98 volts. Adjust the TPS until you have achieved this percentage.
If you can't, replace the TPS and start over.

So, if you have an automatic equipped XJ your TPS has two sides--one side feeds the ECU, and
the other side feeds the TCU. If you have TRANSMISSION issues check the four-wire
connector side of the TPS. If you have ENGINE issues check the three-wire connector side of
the TPS.

For those with a MANUAL TRANSMISSION--the TPS for the manual transmission XJs is
stupid expensive. You can substitute the automatic transmission TPS which is reasonably priced.

RatchetMaster10

Did not know that you had a new exhaust on the jeep. Go do what the others are saying and let us know. When my jeep did what yours is doing it was a clogged converter.

ogune

ok i just chek all of the sencor cps map tps but still aving troble i have no power. but i have a exhaus manafold leak in front ove engien i did a chek on the intake manafold and i have 10psi is this normal ? if i puch the gaz pedel it go to 0 psi and stay there ???? could it be my timing ok intake gasket ???

DFlintstone

There is no timing adjustment. The ECM handles it with the CPS signal. 10 psi? Manifold Vac. is measured in inches, (and drops when you gas it). Fuel pressure is in PSI. Can you be more clear? Just curious, what reading did you get for the CPS?

ogune

for the cps it whas 210ohms and for the vac the 10vac at idiel and go to 0vac at a hier rpm

and why is the vac so low ?? could it be my intake gasket ???

DFlintstone

OK, I think you are talking about inches of vacuum. That's low. Something that is good to check anytime is those manifold bolts you mentioned. Gotta pull the air cleaner. Start at the middle and work out, like three times, all nice and even. One bottom back bolt sucks. The very rear one you can use a swivel with looong extension.

I check for vac. leaks with little short bursts of starting fluid. Manifold gasket, injector O rings, vac lines. If you hit a leak the engine sound will change.

Cruiser might have more to say, he really knows there things well. In the meantime here is one of his wrightups for the CPS. Good Idea to do it since it can take less than 3 minutes and is so important.

Renix CPS Testing and Adjusting
　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
　
Revised 11-29-2011