'90Cherokee

I've had the jeep for several months now and it almost always takes about 3-4 seconds of cranking to start. Once in a great while it'll fire like a 'normal' engine, but it's fairly rare. It has never failed to start (except as noted below) and it usually starts a little faster when warmed up than cold. I've tried priming the fuel sys. with a couple turns of the key and it seems to make no difference. Is this normal or do I have an issue somewhere?

I have done a full T/U and lots of other stuff to it, no change before/after. It has no engine modifications and runs pretty well. The only running issue I've ever had with it was during an off-roading trip in Az about 8 months ago. It was over 100deg., I was running the A/C, and it was mostly low speed uphill the whole way mixed with crawling & idling, as you can imagine that was taxing the cooling sys. and it was running pretty warm. A few times while idling it died and wouldn't restart 'till it sat several minutes. Didn't figure out the cause and it hasn't done it since. Worth mentioning just in case it could be related somehow. I will say I was very proud, and my GF was very happy, to have the only of 3 XJs on the trail that day able to run the AC. One couldn't keep from over heating even without his AC on and the other didn't even try.

salad

Long startups are pretty normal on a Renix. 4 seconds does seem excessive, have you seen cruiser54's Mostly Renix Tips in the technical writeups section?

Radi

Is it cranking slower than it should? Weak battery, corroded connectors? IIRC Renix has to hit a certain RPM while cranking before it tries to fire.

freegdr

Bingo.....faster cranking speed faster starts.

cruiser54

Have you done any of my Tips?

salad

All the other fuel systems do too, I think the Renix ECU just takes a tad longer to wake up.

'90Cherokee

Yes, good stuff there. I've done the coil connections, mine were in good shape but tended to them anyway. Checked but didn't modify the C101 connector, and I think a few other checks.

'90Cherokee

It sounds like it cranks normal and there's been no noticeable change over the last 8 or so months of owning it.

'90Cherokee

That's what I'm thinking, or hoping I guess. Part of me wants there to be something wrong that I can fix, but I'll let it go if it's just a Renix thing. I'll time it today and see if I'm exaggerating the time it takes, very possible. The only other Renix I've been around in a long time was an overheating one on a trip so I couldn't use his startups as a guideline, it was having issues and the guy was being dumb with it.

'90Cherokee

A couple. Thank you for all that! Every time I read through them I want to thank you and haven't. What got me thinking about the startup again and lead to me asking is another thread where a guy is having a problem and asking about the sensor in the dist. You, or someone, said that disconnecting the dist. won't change how it runs much but may make for slow starts. Is there a way to test it to know it's working and what does it do?

'90Cherokee

I was off on my startup time, it's about 3 seconds cold, a hair longer when it's really cold out, and 2-2 1/2 warm. Not extreme, just longer than every other engine I've had, other than my Ducati, but it's the norm for it.

McCaffrey

2ish seconds is normal for mine. It is slower than a newer car, but starts ever time. I keep mine tuned-up and have done many of Cruiser's tips/fixes. Longer start just seems normal.

DFlintstone

I think it need's to both hit 300 RPM and sense two revs. If it stopped with a "tdc" near passing, that and one rev may do it, giving 2-3 seconds. If it stopped with the mark right after, then 3-4 might be more like it. It'll never fire right off. Of course the speed of cranking matters.

It only takes a minute to check a Renix CPS. A weak one will cause slower starts.

We have a check valve in our fuel pump that is known to get dodgy. If you cycle the key to on and off, a few seconds apart, a few times, (the poor man's prime), and it starts sooner, your check valve may be going.

cruiser54

Be thorough with 1,3,4, and 5. You have no C101 connector on a 90.

67 GMC

It's a Renix-Just be thankful it starts! Usually, longer cranking and then eventually intermittent no-starts will lead you to checking the crankshaft Position Sensor.