Exhaust Header and Resto Advice 97 4.0 Limited.

[Doctorbob]

Hi guys,
New member here wanting some advice.
I brought a 97 Grand Cherokee Limited at auction in Brisbane and drove back to Tassie with a transport permit.
My project this winter is to get vehicle registered after fixing a few things. By the way car drove awesome on trip home towing boat.

1. I have removed manifold and exhaust headers and have a crack on 3 grouped pipes which i thought would weld up ok. Alternative was to buy new set but i cannot find the same outlet profile. Mine has a twin outlet with 3 bolt setup and all ones i can find online merge into a single outlet with 2 bolts.
Suggestions appreciated???.

2. Can i bypass/ remove immobiliser as it has a mind of its own. Have new batteries in fob and sometimes have to press it up to 10 or 12 times to disarm and other times only twice.
Very frustrating.

3. Found front left engine mount shagged out which i suspect has contributed to pipes cracking.

Have set myself the challenge to do majority of repairs myself using YouTube and friends knowledge etc.

Your suggestions are appreciated.
By the way car is in mint condition cosmetically and paid $300 at auction.

Regards Rob.

[FRANKIDOWNUNDER]

Hi Rob and welcome to the world of ZG Grand Cherokees. not sure about your headers, have you tried the 4X4 Point site or maybe JPR, Jeep Parts Recyclers, I've used both of them before for my ZG.

Your problem with the key fob may be one of two things. First, make sure that the batteries in the hand piece are making good contact. over time the little metal tabs that they make contact with can bend slightly and not make good contact with the batteries. Be careful though and do not bend them to far or you may risk breaking them off the circuit board.

Second, disconnect the cars battery at the negative terminal and leave it off for a few minutes, then re connect it. This forces the three on-board computers to go back to their initial settings. This model Jeep has a known idiosyncrasy with the remote locking system and when it plays up, which it does if you park too close to phone/ microwave towers all you need do is to disconnect then re connect the battery. I have a battery quick disconnect on mine to save needing tools to do the job.

Do not try to bypass the security system, you risk having it go into lock down and then its a dealers repair needed ( if they remember how to, that is).

Another little tip about this model, if you get engine sensor problems check that the connectors are actually making good contact. My "96 model has round pin connectors and they have given me no end of problems until I remembered about a problem I had some thirty years ago with a system using similar plugs. The fix was simple. Using a very small thin screwdriver ( jewellers type) just close the sockets in slightly, this restores the electrical contact and fixes most of the problems.

Have fun with old bus, they are a great model. I tow a lightweight van with mine.

Cheers, Denis.

[Doctorbob]

Thanks for the reply Dennis,
Have now got exhaust manifold rewelded and added a bridging plate also. I believe I found the cause of exhaust cracks asi noticed r&l engine mounts are very worn. I have ordered a replacement set and now looking for best place to access brass freeze plugs. When I think more about key fob perhaps it is a fuel issue rather than immobiliser?.
Perhaps if there is no improvement after removing neg batt terminal it may point more to a fuel issue.
Looking forward to my next break off work and having another tinker.
Thanks Rob

[FRANKIDOWNUNDER]

Rob, if it is immobilizer then the red lamp on top of the dash would continue to flash. That lamp should stop flashing when the un lock button is pressed on the handpiece. If it does go out then listen for the fuel pump to run when you turn the ignition on. If it does then you are getting fuel pressure to start. As a precaution I have changed both the fuel pump relay and the auto shut down relays, I reckoned that after 20 years they probably needed changing. I also replaced every small fuse in the power distribution box at the same time. Jeep electrical is not that flash quality wise. You can buy a CD of the Grand Cherokee ZG from workshops-manual.com at least thats where mine came from some years back. It covers 1998 models but the general mechanical is the same. (pity the electrical connectors aren't and things like the fuel pump to mention another)
Have you looked at Rock Auto for parts, they are in the US but are quite good and ship to Aus. Just be careful though, LH and RH drive Jeeps use different parts where you least expect them to.

Anyway, keep in touch, PM me if you like and I'll try and help you with further info.

Denis.

[Doctorbob]

Thanks Denis I appreciate your advice. I Will Def be in touch with a question or 2
Thanks Rob

[Doctorbob]

Hi Denis,
Can i pick your brain about a couple of things please.
1. Every time i press kery fob i can hear door locks trying to work but will not actually lock or unlock them, Any thoughts??

2. I brought engine mounts from Amazon just prior to receiving your email recommending RockAuto. Looks a great site. Probably use them for Hsynes manual, fuses and relacement manifold bolts, nuts etc.

I am wondering if my exhaust manifold is an aftermarket extractor as it has a 2 pipe outlet.

Thanks Rob

[FRANKIDOWNUNDER]

Hi Rob, sounds like you either have an aftermarket exhaust manifold. I just looked up the parts catalogue and a genuine exhaust manifold has pipes from cylinders 1,2,3 combining into one leg and from 4,5,6 into another before joining both together to form a single pipe outlet with a flange type coupling.

Sounds a bit like your door locking system is low on voltage as they all should lock and the horn beep when the lock button is pressed. How is the battery and the battery terminals? I replaced all of mine plus the main lead to the power distribution box as corrosion had got into the cables. Also check the earth connections to the body and the engine,these give trouble also. I'd be looking at these before delving any deeper into the system.

As far as batteries go, most battery sellers don't know what the correct one is for this model of European built Jeep and their lists are not correct either. I am currently using a Century DIN 53RMF, not the cheapest on the market but it meets Jeep specifications and fits correctly into the tray with good clearance from the top radiator hose.

Denis.