Hi,
I have an 89 4x4. Recently I noticed some occasional hesitation at freeway speeds. Then it got progressively worse within 5 drives or so. It doesn't accelerate well and hesitates/bogs. I pulled the codes and got 2-1, 5-1, and 7-1.
I'm hoping to get some help ad to where I should start. Also if it matters, my van tends to run on the cold side for quite a while after starting and running.
Any suggestions on where to begin?
Thanks. This forum is great.
The codes are in your manual or on the library section of this website you can look at them or download them-According to the codes 21 says O2 sensor(get a new one), 71 is EGR(does it look melted?) and 51 says Switch signal -tps maybe-I'd worry about this after the cat is checked. I'd look into your Catalytic converter-might be clogged by the symptom of it bogging down more and more.
When did you last change your spark plugs?
Take my views with a grain of salt-I usually figure things out the hard way.
Thanks. It's definitely been a while since the plugs were changed. I've had the van for about 11 years but prob only put 50k on it since then. I'll try to take a look at the Cat and the Egr. Change plugs and O2 sensors as well. Will the damaged EGR be obvious? Sounds like I've got some work to do.
Thanks again.
Hi & welcome to TVT!
Originally Posted by djshimon
When the primary o2 sensor fails the ECU goes into a "limp" mode as it doesn't have the information it needs to correctly mix the fuel. Running lean can create serious issues, so the limp mode is set to make the van run a bit rich. Running rich will make the economy & the power go down. If left in this mode for very long it can plug up the cat converter. When the cat converter plugs up, this will create exhaust back pressure and the result is serious power issues and over temp issues with exhaust components (EGR included). The TPS (Throttle Position Sensor) is also an emission device designed to help the ECU provide the correct fuel mix (based on position of your throttle). If the ECU doesn't know throttle position, this can exasperate the problems created by a bad o2 sensor.
Replacing the o2 sensor(s) is easy. Here's a link to a thread that gives part numbers: http://www.toyotavantech.com/forum/s...or-part-number
Replacing TPS is a bit more involved. You'll need to remove the throttle body to do that one. While it's off it's a good idea to clean it up. Here's a thread where this is discussed: http://www.toyotavantech.com/forum/s...-Throttle-Body
Replacing cat with a CA approved unit can be quite expensive. Because of this I'd probably do the other things 1st, clear the codes, then see if code 71 comes back. If you still have power problems, and if code 71 comes back, then it's likely the cat converter is toast. Depending on how much corrosion is on the cat mounting bolts, replacing that can be easy or hard. If the bolts are badly rusted, you may decide to take to an exhaust shop and let them do the work.
And definitely take care of the other tune-up issues. Be sure to use high quality platinum spark plugs. I prefer Denso #P16R, but others will work here (I don't like Bosch). Be sure to replace the fuel & air filters too. OEM spark plug wires last a long time, but the van is getting old. If you don't know when or if they have ever been replaced, then probably a good idea to do those as well. Same goes for the distributor cap and the rotor. Drive train fluids should be replaced in 60k mile intervals, and engine oil S/B replaced every 3 - 5 k miles..........but I'm sure you already know that. Tim
Thanks Tim,
Do you think the 5-1 code- EGR system could cause this issue as well? Should I address this last, after 02 sensors and TPS?
Also, do you have a link to a good source for a new TPS?
Thanks for your help.
As previously discussed, code 51 is most likely your TPS. Code 71 is your EGR temperature getting too hot. It's possible it's getting hot due to the extra contaminants the cat is burning off, so I'd wait and see how it does with the other issues fixed. I'm pretty sure that in the throttle body thread (linked above) there's a link to a new TPS. When I need just one (and nothing else), I'll usually purchase from Amazon (about $35 w/free shipping). Rockauto.com has them for $28 or $29, but the shipping will usually make up the difference. Sometimes I make large orders from rockauto & will get 5 or 6 of them (then the shipping is worth it). As discussed in that other thread, I've been using Bech Arnly units (made in Italy) and I believe they are quality units. If you can afford Toyota, they will want roughly double the price, but not sure if they are any better. Tim
Thanks for the input. I'm starting to understand this more and more!
Another question- Anyway to check the CAT easily? The bolts look pretty locked up. I suppose I will have to break them and look in, then replace with new ones?
Thanks again.
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