• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Takes way to long to start. Any ideas?

C

crazycracka

NAXJA Forum User
Location
The OC, Oregon
So I know that a lot of no starting or long starting threads have been posted. Yet I haven't cured this problem.

Normal starting takes 4 or 5 seconds of cranking. Then it runs fine.

If I prime the system 1,2 or even 3 times until Pump no longer kicks on does nothing. Still same starting time.

If I floor the pedal and try to start it doesn't start at all.

If I spray carb cleaner/Starting fluid into the intake it Fires right up...

Starting time doesn't change cold or warm. Or if I start it then turn off and start right back up. The rail seems to hold pressure for awhile after being shut off. Not sure how much, I haven't got a pressure gauge yet.

The only thing so far that changes the start up time is spraying carb cleaner or starter fluid.

I have cleaned the IAC, changed plugs, cap, rotor, air filter, breather. But obviously it is fuel related.

As I said it runs good after started its just the starting time that is bugging me.

Any ideas??

TIA
 
Year? Crank time may vary by year.

4 to 5 seconds was "normal" and is now taking longer or was shorter and now taking 4 to 5 seconds?
 
Do a search on check valve.
 
Pelican said:
Year? Crank time may vary by year.

4 to 5 seconds was "normal" and is now taking longer or was shorter and now taking 4 to 5 seconds?
Click to expand...

I have only owned it a few months but it has been like this since I bought it.

And yes the return check valve for fuel. But if that were the case would the fuel rail hold pressure for minutes after being shut off? Another thing I have read about the check valve is that priming before starting could diagnose this problem. But as I said Even after priming the start time doesnt change..
 
You're probably right.

Just for good measure, I would run a can of BG44K through the fuel system. I run a can about every 10k in each of my vehicles. It is a miracle in a can for cleaning fuel systems and removing built up carbon.
 
b16a90teg said:
I have only owned it a few months but it has been like this since I bought it.

And yes the return check valve for fuel. But if that were the case would the fuel rail hold pressure for minutes after being shut off? Another thing I have read about the check valve is that priming before starting could diagnose this problem. But as I said Even after priming the start time doesnt change..
Click to expand...


87-90 jeeps take at minimum 2-3 seconds to start up. More if in need of a tune up.

But even brand new they took 2-3 seconds to even try and run. It's to do with the RENIX computer.. Who knows, maybe the engineers wanted more oil to cycle or something.
 
b16a90teg said:
LOL sorry That would probably help a bit. Its a 1990 laredo 4.0l.. 4wd etc etc..

When I first bought it I did run a can of seafoam through the gas tank and through a vacuum line.
Click to expand...

Perfectly normal for RENIX - the system won't fire the ignition or fuel injectors until it sees 300rpm at the CKP and get a valid signal from the CMP in the distributor. It can "guess" without the CMP signal (I've checked this,) but that 300rpm is vital.

If you want to shorten the cranking time, you'll want to upgrade your mains cables (allowing more current to flow to the starter motor, and getting it up to speed faster,) and improve the chassis ground (OEM has it grounding through that stupid open braid strap and by way of the engine block.) Clean the contact patches of paint down to bare metal and apply corrosion inhibitor on reassembly, replace the screws if necessary, and replace the leads as required (min. 8AWG.) Adding a secondary chassis ground (similar treatment, min. 8AWG) from the fenderwell to the battery negative post usually helps as well.

Hit me backchannel if you want to know more. However, this is a known issue with RENIX, and nothing to be terribly surprised about (I've had five RENIX rigs to date...)
 
5-90 said:
Perfectly normal for RENIX - the system won't fire the ignition or fuel injectors until it sees 300rpm at the CKP and get a valid signal from the CMP in the distributor. It can "guess" without the CMP signal (I've checked this,) but that 300rpm is vital.

If you want to shorten the cranking time, you'll want to upgrade your mains cables (allowing more current to flow to the starter motor, and getting it up to speed faster,) and improve the chassis ground (OEM has it grounding through that stupid open braid strap and by way of the engine block.) Clean the contact patches of paint down to bare metal and apply corrosion inhibitor on reassembly, replace the screws if necessary, and replace the leads as required (min. 8AWG.) Adding a secondary chassis ground (similar treatment, min. 8AWG) from the fenderwell to the battery negative post usually helps as well.

Hit me backchannel if you want to know more. However, this is a known issue with RENIX, and nothing to be terribly surprised about (I've had five RENIX rigs to date...)
Click to expand...

Well thanks for the info.. Tomorrow I will go through the cables and see if that helps.. Maybe ill try a different battery too one with higher CCA..
 
b16a90teg said:
Well thanks for the info.. Tomorrow I will go through the cables and see if that helps.. Maybe ill try a different battery too one with higher CCA..
Click to expand...

Trying a larger battery will be of limited utility - the "choke point" you're trying to address that way is the mains lead to the starter motor, and not the battery itself. The starter motor is good for about 160A instantaneous draw on RENIX (I've checked - both at "no-load" and in starting conditions. That 160A figure is in starting condition, cranking the engine,) and it's already limited by the use of the 8AWG OEM mains lead.

If you want to check to see if it's the supply to the starter motor, try using a booster cable from the battery + post to the large post on the starter motor solenoid - they're usually something larger (a decent set will be 4AWG.) Even if they're smaller - some sets are 10 to 8AWG - the additional conductor will still help - and two 8AWG conductors, as I recall, effectively equal 2AWG.

If it cranks faster that way, think about upgrading your mains cabling - your battery isn't the problem.
 
x2 on 5-90's input.
 
5-90 said:
Perfectly normal for RENIX - the system won't fire the ignition or fuel injectors until it sees 300rpm at the CKP and get a valid signal from the CMP in the distributor. It can "guess" without the CMP signal (I've checked this,) but that 300rpm is vital.

If you want to shorten the cranking time, you'll want to upgrade your mains cables (allowing more current to flow to the starter motor, and getting it up to speed faster,) and improve the chassis ground (OEM has it grounding through that stupid open braid strap and by way of the engine block.) Clean the contact patches of paint down to bare metal and apply corrosion inhibitor on reassembly, replace the screws if necessary, and replace the leads as required (min. 8AWG.) Adding a secondary chassis ground (similar treatment, min. 8AWG) from the fenderwell to the battery negative post usually helps as well.

Hit me backchannel if you want to know more. However, this is a known issue with RENIX, and nothing to be terribly surprised about (I've had five RENIX rigs to date...)
Click to expand...

I'm trying to understand this... If he sprays starter fluid in it fires right up other wise long delay. If the delay is because the ecu won't fire the injectors or spark then how does the starter fluid help? If its not sparking then whats firing the starter fluid off?

I'm just having one of those moments, you guys know what you're talking about but I'm just missing it ha.
 
iwannadie said:
I'm trying to understand this... If he sprays starter fluid in it fires right up other wise long delay. If the delay is because the ecu won't fire the injectors or spark then how does the starter fluid help? If its not sparking then whats firing the starter fluid off?

I'm just having one of those moments, you guys know what you're talking about but I'm just missing it ha.
Click to expand...


I was wondering the same thing. The only thing I can think is that the computer controls the Injector pulse and not the spark? God question though i didnt even think of that. lol
 
On eBay the seller jbass195 sells a 3/8" one-way fuel check valve, $14 + $2 s/h.

The Renix needs to crank up to 300 rpm before it is going start.

Good battery with upgraded cables, good starter will make it happen faster. I doubt if a gear reduction starter would be worth the cost, about $300, for a few seconds of your day.
 
Also, how old is the starter motor? Two of our fleet were lazy starters (all HO) but a few years ago, I had to replace-again- the starter in my '92. I bought brand new at Advance-Palladium, IIRC, and WOW, it starts in a hurry. I honestly wish it would wait until some oil was moving! As electric motors age, and starters are way small due to weight and packaging issues, they start to need more and more current to do their job. They take from whatever else might be needing juice, namely the ignition. Once an electric motor comes up to speed, it's current need diminishes somewhat, freeing up some power to do other things. An old motor will keep struggling, and hogging the power, taking its good old time to hit the required 300 RPM crank speed.
 
iwannadie said:
I'm trying to understand this... If he sprays starter fluid in it fires right up other wise long delay. If the delay is because the ecu won't fire the injectors or spark then how does the starter fluid help? If its not sparking then whats firing the starter fluid off?

I'm just having one of those moments, you guys know what you're talking about but I'm just missing it ha.
Click to expand...

Because ether has an absurdly low AKI, and will usually ignite under compression - similar to how a Diesel ignites its fuel.

The extra "kick" of the ether firing would be enough to spin the crank a little harder, so that would speed things up.
 
I have an extra BMW check valve.. that I could sell. Was going to install it on my buddy's jeep, then he got rid of it.
 
5-90 said:
Because ether has an absurdly low AKI, and will usually ignite under compression - similar to how a Diesel ignites its fuel.

The extra "kick" of the ether firing would be enough to spin the crank a little harder, so that would speed things up.
Click to expand...

That's what I was starting to think, that it was acting like a diesel. Which is pretty cool I think...
 
You must log in or register to reply here.

Similar threads

N
New Engine is Hard to Start
Replies
0
Views
34
NGThomas
N
M
92 XJ ECU connector
Replies
5
Views
138
Rob Mayercik
R
S
Fuse Panel removal
Replies
6
Views
1K
lawsoncl
L
N
Severe stumble, misfire and no start issues
2
Replies
27
Views
4K
maxbraketorque
M
W
Fuel Pressure Regulator & Long Cranks
Replies
1
Views
1K
Anak
Anak
Back
Top