tsarang

I got the timing belt change complete. everything looked good. made sure all the timing marks lined up by turning the crank twice from TDC to TDC. looks perfect. got the distributors and rotors installed perfect But When I start the car it starts immediately with RPMS at 3000-4000 as usual then after a couple of secs they come down and car stalls, after this it crank's but does not fire up. I can make it start after a lot of cranking and pushing on the gas pedal. It will stall if I let off the gas. The car runs real rough with lots of vibration when I do this.

I had the car started long enough to get near operating temprature and it gave a p0304 code, i changed the cylinder spark plug and wire as I found the spark plug wire to be out of specs(>40Kohm). I cleared the code and restarted. Still the engine gives me same code. I cleaned up the distributor and rotor connections, switched them. still the same. Engine hard starts, runs rough with shudder. will not idle and it die's if i let go of gas.

I had the car sitting for about two months now through the 14F weather, do you think its because of bad gas?. I dont think its ignition because I have already checked spark, resistances of the coils, wires, plugs etc. I can hear the fuel pump and can smell gas so that also cannot be the culprit.

this is what I am thinking might be the problems

a) Bad gas, fuel filter
b) IAC valve (idle-air control (IAC) valve, vacumn leak??)
c) Crank sensor?

I am stumped on this one, Please Help!!!!

rob22

Maybe you could keep the engine going long enough to strobe the timing, see attached (for my '97). Did you install a new tensioner?

PureDrifter

iTrader: (10)

sounds like the timing is wayyy off.

check the position of the rotors, and run a timing light on it and see where it's at.

tsarang

Thanks all for the Quick reply.

I have to admit this is my first time changing the timing belt. But I did a lot of reading and research before i touched it.

i am following this guide for instructions
http://www.lexls.com/tutorials/engine/timingbelt.html

a) I have arranged the crankshaft at TDC, Top dead center (by setting crankshaft at 0 mark with the timing guide) as in this pic
http://www.lexls.com/images/timingbelt/timingbelt21.jpg

b) I have the camshaft and timing belt set to match the timing marks, as in these pics
http://i248.photobucket.com/albums/g...e/CIMG2096.jpg
http://i248.photobucket.com/albums/g...e/CIMG2097.jpg

When I turn from TDC to TDC all the camshaft marks align perfectly with the timing marks. I double checked the rotors too, they are installed correctly. there is a pin grove in the camshafts where the protrusion from the rotor assembly fits into, its impossible to get it wrong (I have done 2 tuneups on this car already so i am pretty confident).

I know this tutorial has been done on a 1992-1994 1st generation Lexus. Is it possible that the TDC method is not applicable for my Model? 1996. I know they are a different engine internally than the previous generation. did I follow the right method to fix timing?.

another thing I found out while changing the timing belt is that there was no timing drill mark/notch on my crankshaft. the lexls tutorial says align the crankshaft mark/notch to the belt and there was no notch!!!!. I aligned the LH CAM with the timing mark on the plate, then I got the timing mark on the belt to match it and stretched it towards the Crankshaft pulley then tucked it inside making sure there was no slack or missing teeth between both LH CAM and Crank. Then I matched the Timing mark on the RH pulley to the plate and proceeded with aligning the belt mark on the pulley, it aligned perfectly. there was slack between the RH pulley and Crank which went away after i reinstalled the OLD tensioner. I then proceeded to put the timing cover and the harmonic balancer pulley, rotated from TDC to TDC two times, all the CAM mark aligned perfectly to the marks on the Plate. This is the only test given to verify timing and the only one i Knew untill "rob22" mentioned about strobing for timing.

This is the only test I knew, I performed it again and again to make sure timing is correct, am I wrong here?, is there a different procedure for a 96LS". Where can I get the strobing/timing testing light from?

This Forum has always been a boon. Appreciate your help all.

rob22

This might be redundant but here it is anyway. Let us know how this works out...I gotta do mine a few thousand miles!

http://www.lextreme.com/timing2.html

Amskeptic

Once you have the crankshaft pulley and timing scale on, a perfect alignment between the notch on the pulley and the "0" on the scale is accurate enough to recheck the camshaft pulley notches with the belt. They are the subtle marks, not those big cam sensor trigger tabs.
Colin

nthach

Line up the timing marks. On the crank gear, the mark here is a dot on one of the teeth and the corresponding mark should be on the lip of the oil pump/pan junction. The cam gear timing marks are a dot as well, with a mark on the rear timing cover. OEM Toyota t-belt have marks that will greatly assist installing the belt onto the respective marks. Once tension is applied and the crank is turned, the marks will not line up with the cover and gear marks - BUT the gear and cover marks MUST line up!

Also, I think the TSRM on the 1996-newer motors calls for rotating the crank 50 degrees after TDC has been set, or that is for the VVT-i motors?

atoyot

i am not super familiar with this motor yet.

On some other toyota motors, it is easy to think the motor is at TDC by looking at the crank pulley, when in fact it's 180 degrees off.

I did this on a land cruiser once. Started it and it revved real high, then sputtered and quit. The timing was off 180 degrees. Once i rotated the crank again, it was perfect.

rob22

Any chance you installed the timing belt guide (step 23 in LexLS's writeup) backwards? I think that has a trigger that talks to the crankshaft position sensor.

Another idea is you could check compression in any one of your cylinders. I would think that would answer atoyot's comment...poor compression would indicate that you're off.

tsarang

Thanks rob22 for the timing belt change docs. You had one doc in there for 95-97 LS400 which partly resolved my dilemma. When I installed the Timing Belt, I had issues starting the timing belt as there was no dot or drilled mark on the Crank Rotor. This doc makes it very clear(I will upload the same doc again for others to follow).

Crank Rotors for 95-97 model is completely different from the 98-2000, They look different and do not have the drilled mark, instead they have a small notch, very faintly visible, I will upload pics. Cam rotor are also different, with different markings look different from 98-2000(I will upload pics for these too)

I recommend and advice not to follow procedure from 98-2000 as the procedure is slightly different and confusing. I say this because lots of people like me have 2000 manuals downloaded from this site.

Now Back to my Issue, I redid my Timing belt yesterday, followed the doc to perfection. Went TDC to TDC, All good. Car cranked and fired up like it normally does, no shuddering this time, It tried to settle to its idling rpm then there was a noise(BUDUMM), I dont know if it was backfiring or something relating to engine starving out of gas, it died.

the next time it will crank but not start, at times it will look like starting, catch a couple or rpms and die's down. It fires up if i give some throttle. However I feel a difference, this time engine does not shudder anymore like it did before, much smoother at higher revs, but it will not idle on its own, the moment I let go of the throttle it will die.

Heelllllpppppp!!!!! I am so close to towing this to the Shop.

tsarang

Uploaded doc again for 95-96-97

rob22

Couple of questions, these might be "dumb" but here goes:

1. When you redid the timing belt, did you find that you were off by a tooth the first time you did it?

2. When you restart the engine, everything is back together and reconnected, correct? In particular your MAF sensor is hooked back up?

3. All your hoses are tight, right...no leaks/false air coming into the manifold?

4. If you pulled any relays, make sure they're back...the fuel pump comes to mind but I don't think you'd be pulling that for the timing belt anyway

As an alternative to towing to the shop, if you have a friendly indy mechanic you could probably pay him a few bucks to stop by and have a look...might be the cheaper route.

tomeyeman

New poster here. I figured I'd jump in at the end of this thread. 1996 LS400 with 175,000. Awesome car overall.

I just changed my timing belt along with water pump (the reason for doing the work). They were changed 3 yrs ago at the dealer but the water pump already went bad and the car was overheating and I had no heat. (for the record, the plastic propeller on the water pump came loose from the shaft-- spinning freely--cheap plastic crap... but I digress).

While I was at it, I change the plugs, wires, both rotors and distributor caps. Figured I might as well do it all while I was in there.

I check, double check, and then triple check the timing marks to get the belt right (which means it still might not be right ). So I get it all back together and it turns over but doesn't start.

After 3 days of reading threads here, I figured my rotors were 180 degrees out of wack. So I rotated them and BOOM, it starts..........but it doesn't sound pretty. Lots of knocking and hard starting. I double check the plugs and wires--all good.

I hooked up a timing light and it appears to be dead on at 10 degrees BTDC. No codes are coming up. Sure sounds like the timing is off. I'm getting ready to break it back down (much easier the 2nd time ) .

So my question to all you guys smarter than me: Can the timing be off if the timing light shows it to be on??

PureDrifter

iTrader: (10)

did you put the belt on right....?

bmoore

What kind of knocking? :worried: