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Alex
Alex, ASE Master Technician
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Ive replaced the EGR module on my Suzuki Sidekick, 1992 model,

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I've replaced the EGR module on my Suzuki Sidekick, 1992 model, 1.6 L engine. I had the vacuum pressure test done on my EGR valve and it's fine. I replaced the EGR gasket as it was blown. My question is about the hose that runs from the bottom of the EGR module to the side of the EGR valve (connects to a bent steel tube that comes out of the EGR valve). For whatever reason, this line/hose (the rubber one that runs from the EGR mod to the EGR valve) blows off--either from the bottom of the EGR mod or from the pipe that connects to the EGR valve. Is this an indication of a bigger problem or do I just need to replace the hose that runs from the EGR mod to the EGR valve? Should I put hose clamps on it on both ends? I guess my biggest concern is whether this is a simple fix solved by replacing the hose with a new one and possibly securing it with some clamps or is this hose blowing off (it happens when I down shift under load from 5th to 3rd, or whenever I have to punch the accelerator hard) a symptom of some other problem?
As long as the vacuum hose fits snuggly over the nipple on the EGR valve, it should not blow off. If it is blowing off, I would suspect the EGR modulator filter diaphragm is leaking, allowing exhaust back-pressure past the diaphragm in the modulator and blowing the vacuum line off of the nipple. Another possibility is that the EGR valve diaphragm is leaking, allowing exhaust backpressure to the vacuum hose.

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Check filter for contamination and damage. Using compressed air, clean filter.

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Remove EGR modulator and plug nozzle with finger. Blow air into another nozzle and check that air passes through to air filter side freely.

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  • Connect vacuum pump gauge to nozzle "P" and plug nozzle "Q" with finger. While blowing air into nozzle "A", operate vacuum pump gauge and check that vacuum is applied to modulator. Then stop blowing nozzle "A" and check that vacuum pump gauge indicates "0" (zero). If check result is not satisfactory, replace EGR modulator.
  • After checking, install modulator and connect hoses securely.


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Edited by Alex M on 8/1/2010 at 6:15 AM EST
Customer: replied 7 years ago.
Thanks for the reply so far: the EGR module is brand new--I had a mechanic vacuum test the EGR valve, and it tested OK. As far as the EGR valve diaphragm leaking--should the vacuum test not have ID'd whether it was leaking or not? So, if there is exhaust backpressure from the EGR valve, should I be able to feel it coming out of the bent tube that emerges from the side of the EGR valve with the hose disconnected and the engine running? Or, should there be a suction/vacuum action at that elbow with the engine running (no hot gas emerging, but air being sucked in)? For clarification purposes, I'm talking about the hose that runs from the bottom of the EGR module to the pipe elbow that comes off the side of the EGR valve (this is the one that's blowing off)--it's the biggest of the three hoses--the top two that connect to the EGR mod on the top of it at P and Q are considerably smaller--they do not blow off.
There should only be suction at the vacuum hoses that are connected to manifold vacuum. And you should not be able to feel any pressure coming from any given location in this system. The problem is that manifold vacuum can not blow the vacuum hose off since it is creating suction. Only exhaust back pressure should be able to blow the hose off in this system.
Customer: replied 7 years ago.
OK--so since the EGR mod is brand new, does that mean that the only other way that the biggest of the three vacuum hoses--the one that connects to the bottom nipple on the EGR mod--does that mean that the only way it can blow off is if the EGR valve is faulty in some way?
If the EGR valve itself tests ok and holds vacuum, then I don't think the problem would be with the valve. Most likely the problem is clogged EGR passages, which is quite common on this vehicle. The EGR valve opens to allow exhaust gas through the passage, but if the passage is clogged this can cause back pressure in the system and blow the hose off. Looking at this diagram it's easy to see how exhaust gas backing up in the manifold from clogged EGR passages could try to escape through the vacuum port to the EGR modulator:

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You'll want to remove the EGR valve and clean the EGR passages with something long and flexible, preferably a speedometer cable attached to a drill. However, there are many things that will work well enough to clean the passages.

Edited by Alex M on 8/1/2010 at 5:57 PM EST
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