Start up rattle prevention question (1 Viewer)

[tusk74]

Two Questions I'm interested in getting opinions on:

1. Is there reason to believe 1fz's start up too fast, limiting the amount of oil to the bearings causing the rattle?

2. If one could disable the EFI for a short time period during start up to allow the oil to circulate, how long of a time period would we be talking?

I've been thinking about a simple solution that wouldn't involve O-Rings.

 

[RavenTai]

my understanding is the start up rattle is the timing chin slapping the sides of the timing cover before the oil pressure actuated chain tensioner takes the slop out, the 22r had a similar problem, on that motor in extreme cases the cain would cut through the timimg cove in to the back of the watter pump cavity.

you can try using the smaller filter as it gets the pressure up sooner, also getting the start up rpm down (search for the O-ring trick) will help, if the above is not enough seach for Robbie's post about enlarging the oil inlet hole in the tensioner. it is externally accessable on the right side up front.

 

[RickyRacer]

RavenTai may have the solution or part of it....
I've recently had similar sounds at start up, one of which was a little extreme for my liking.
I found a shop in town that specializes in Toyota and Lexus service and only uses OEM parts.
I had my LC in for some small repairs and an oil change (didn't have the time to do them myself) and he used the small OEM oil filter. I've used Mobil 1 in the past.
No more rattle and high revs at start up.

 

[whodat]

I just switched to the small YZZ filter, and still have the startup rattle

wd

 

[tusk74]

I was thinking of wiring an adjustable current delay relay in the EFI fuse circuit and experimenting with the delay time. The current to the EFI wouldn't switch on until the programed time limit was up. This would allow the starter to crank the engine a few seconds longer until the relay allowed the current to flow through. I was just curious as to how long the starter would have to crank to provide sufficient oil to the tensioner? If the carnk time was more than 4 seconds, I don't think it'd be worth it.....too hard on the starter. On the other hand, if the crank time was 4 sec. or less, this would be a 15 minute fix for an annoying problem.

Just a thought.

 

[cruiserdan]

3 or 4 seconds of cranking is usually enough to get the "blood" pumping. I think 1FZs fire off too fast and the pre-programmed fast idle gets them moving in a hurry. I was assured several years ago by a friend at TMS technical that it was not a durability issue and that it was considered normal operation. I would like to see them spin for a couple seconds before catching and then idle a bit lower. They idle fast and furious in order to heat up the exhaust quicker so the cats will light-off sooner (read lower emissions).

D

 

[robbie]

I believe that the chain does not hit the timing cover, but hits the gears creating this sound when the tension is loose. The stationary guide is coated with a hard rubber, where the tensioner side(damptner) is hard plastic coated, the chain should not hit the timing cover at any time unless the guide system get hurt. Delaying the start may help, but I have experenced several trucks that are hard to start but also have this rattle after i get them started. I have seen some trucks with over 200k miles with no apparent problems with the engine's ablitly or durability (except that it is high milage). sorry not be of more help. I have done a couple of the hole enlagements with some sucess, meanings most worked, one lessened the rattle. so 4out of 5 worked by enlageing the hole to .040 from before, becareful to not go any futher than necessary, you may hit the spring inside. later robbie

 

[tarbe]

My '97 cranks for several seconds before firing. I thought this was by design to get the oil flowing prior to hitting the bearings with a load??

 

[Bear80]

Personaly my 97 has a slight dull knock at first crank (almost like piston slap) for just a second. Now I belive the rattle being noted here is what my father's 95 had. His wagon would crank and shoot up to 1800 rpm and there would be a rattling sound. He found some writeup's about using washers?? to lower the idle. I belive he found them on OZ posts. After lowering the initial high idle and using a larger K&N, the rattle has gone away. We both use the 3001 k&n I think, can't check since I'm at school. I think it's used on f-150's, but we use it because it's the size of the japan made filter and has all the anti-drain back features.

 

[MoJ]

Bear-
The "fix" you're describing came from a gentleman on the 80scool list. Here's the link:
http://www.safari4x4.com.au/80scool/tech/fast_idle/fast_idle.html

I've wanted to do that mod for some time but have been hesitant as I feel it only treats the symptoms.

The high idle start up drives me crazy. Mine takes 2 minutes to go down to normal idle and sometimes I don't have 2 minutes to wait. It worries me most as it doesn't seem good to engage the drivetrain while the idle is up so high but then again I'm 1 banana. Other than the o-ring described in the link above I've yet to hear anyone say, "I did X and it cured the high start up idle."

 

[stlcruiser]

Bear-
The "fix" you're describing came from a gentleman on the 80scool list. Here's the link:
http://www.safari4x4.com.au/80scool/tech/fast_idle/fast_idle.html

I've wanted to do that mod for some time but have been hesitant as I feel it only treats the symptoms.

The high idle start up drives me crazy. Mine takes 2 minutes to go down to normal idle and sometimes I don't have 2 minutes to wait. It worries me most as it doesn't seem good to engage the drivetrain while the idle is up so high but then again I'm 1 banana. Other than the o-ring described in the link above I've yet to hear anyone say, "I did X and it cured the high start up idle."

I THOUGHLY CLEANED MY THROTTLE BODY AND IT CURED THE HIGH START UP IDLE!

 

[MoJ]

That's what I needed to hear. Sometimes the use of caps is appropriate. Give some more detail - how long ago did you you clean it? Still good? What's your current start up idle from cold? Why didn't the Rams do better this year? WTF happened to the cards? (stl=st louis?)

Gracias
Jason

 

[ChuckD]

Start up rattle prevention

Someone recently suggested that after cleaning EGR system his fast start was cured. There is some form of blockage in the throttle body that throws a code 71. Perhaps this passage is related to fast start mystery. Since I'm the lucky one with a 71 the cleaning might reveal something.
ChuckD

 

[stlcruiser]

Purchased 80 with 84,000 miles. Inital start up rev to 2,000 rpm then settle down to 1,800 and sustain for 3 - 4 min. until it would slowly creep down as engine approached operating temp.

Even a hot engine would start out with the 2,000 rpm rev.

Tried 1 oring. (no change), Tried 2 o-rings. This eliminated the high revs, however as the engine warmed up, it would not eventually cut out. The ECU just would not accept this after multiple start cycles trying to "learn" the new perameters.

Afer a good throttle body cleaning at 106000 miles, initial start up is 1,200 and that lasts only for 1 or 2 seconds. It immediatly drops to 1,000 and quickly to 800 and ultimatley 650 idle afer a couple minutes. At 130,000 miles the high idle has not returned.

Rams shouldn't have been there in the first place. Cards were to busy congradulating themselves for the playoffs to care aboult the world series.

Steve
94 130,000

 

[Beowulf]

Steve,
Did you remove the 2 o-rings before you cleaned the throttle body? After?

-B-

 

[stlcruiser]

Beo:

O rings were removed after ECU didn't take kindly to them. High idle came back. Then performed the throttle body cleaning approx. 2 months later.

Steve
94, 130,000

 

[semlin]

there are old posts on start up idle and you should read them. cleaning throttle body is NOT a solution for everyone and NEITHER is fixing the EGR. As best I can tell removing and replacing the throttle body sometimes improves the start up idle for a random period of time.

As for the rattle, I had this when I bought the truck but after switching to mobil 1 and the small good filter it has never recurred in 20,000 miles of driving. others have not had the same results.